Статті в журналах: "COATED PDMS"

1

Tang, Daibin, and Enzhou Liu. "Facile Fabrication of Robust and Fluorine-Free Superhydrophobic PDMS/STA-Coated Cotton Fabric for Highly Efficient Oil-Water Separation." Coatings 13, no. 5 (May 19, 2023): 954. http://dx.doi.org/10.3390/coatings13050954.

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Oil–water separation using special wettability materials has received much attention due to its low energy consumption and high separation efficiency. Herein, a fluorine-free superhydrophobic cotton fabric (PDMS/STA-coated cotton fabric) was successfully prepared by a simple impregnation method using hydroxyl-capped polydimethylsiloxane (PDMS-OH), tetraethoxysilane (TEOS), and stearic acid (STA) as precursors. The investigation found that the cross-linking reactions between the hydroxyl groups of PDMS-OH and hydrolyzed TEOS enabled a strong interaction between PDMS-OH and cotton fabric. Furthermore, a suitable roughness surface of coated cotton fabric was established by introducing STA due to its long chain structure. The contact angle of this composite can reach 158.7° under optimal conditions due to its low surface energy and desired roughness. The oil/water separation efficiency of PDMS/STA-coated cotton fabric is higher than 90% even after 10 cycles of oil–water separation, and the oil flux can reach 11862.42 L m−2 h−1. In addition, PDMS/STA-coated cotton fabric exhibits excellent chemical stability and durability under extreme conditions such as strong acid (HCl, pH = 1~2) and alkali (NaOH, pH = 13~14), and the hydrophobicity of PDMS/STA-coated cotton fabric was decreased to 147° after 300 cycles of abrasion testing.

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2

Ding, Yin Yan, Bi Xu, Feng Yan Ge, and Zai Sheng Cai. "Robust Superhydrophobic and Photocatalytic Cotton Fabrics Based on TiO₂-SiO₂-PDMS Composite Coating ." Key Engineering Materials 671 (November 2015): 225–30. http://dx.doi.org/10.4028/www.scientific.net/kem.671.225.

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In this work, self-cleaning cotton fabrics were prepared based on the TiO2-SiO2-Polydimethylsiloxane (PDMS) composites. TiO2-SiO2 composites were synthesized by depositing TiO2 nanocrystals onto preformed porous SiO2 and PDMS was used to enhance the linkage between TiO2-SiO2 composites and cotton fabrics. The TiO2-SiO2-PDMS composites coated cotton fabrics show superhydrophobicity with a water contact angle of 157°because of the abundant of methyl groups and hierarchical roughness features of the coated cotton fabrics. Meanwhile, the TiO2-SiO2-PDMS composites coated cotton fabrics display photocatalytic property, which were analyzed based on the removal and degradation of rhodamine B (RhB) under ultraviolet light. Abrasion resistance test indicates that the coating possesses a good mechanically durability.

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Shi, Dongyan, Dan Ma, Feiqing Dong, Chen Zong, Liyue Liu, Dan Shen, Wenji Yuan, Xiangmin Tong, Hengwu Chen, and Jinfu Wang. "Proliferation and multi-differentiation potentials of human mesenchymal stem cells on thermoresponsive PDMS surfaces grafted with PNIPAAm." Bioscience Reports 30, no. 3 (December 15, 2009): 149–58. http://dx.doi.org/10.1042/bsr20090026.

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The thermo-responsivity of PNIPAAm [poly(N-isopropylcarylamide)]-grafted PDMS [poly(dimethylsiloxane)] surface is a property that could be feasibly used for detaching cells adhered on the surface. We used benzophenone-initiated photopolymerization to graft PNIPAAm on PDMS substrates to construct the PNIPAAm-grafted PDMS surface and this PDMS surface was highly thermo-responsive. hMSCs (human mesenchymal stem cells) were used to analyse the proliferation and multi-differentiation of stem cells on the PNIPAAm-grafted PDMS surface. The results showed that hMSCs could adhere on the PNIPAAm-grafted PDMS surface at 37°C and form cell colonies, and then become fibroblastic. The proliferation potential of hMSCs on the PNIPAAm-grafted PDMS surface was not significantly different from that on a plate surface coated with gelatin. However, as it proved easier to detach cells from the surface, by changing temperature, a higher viability of detached cells could be obtained with the PNIPAAm-grafted PDMS surface, using a temperature shift, compared with a gelatin-coated surface, where cells are detached by treatment with trypsin. hMSCs on the PNIPAAm-grafted PDMS surface were induced into osteoblasts, adipocytes and neurocytes under osteogenic medium, adipogenic medium and neurogenic medium respectively. The PNIPAAm-grafted PDMS surface was favourable for osteogenesis of hMSCs, although the potentials of adipogenesis and neurogenesis of hMSCs on the PNIPAAm-grafted PDMS surface were similar to those on the plate surface coated with gelatin. The above results demonstrate that the PNIPAAm-grafted PDMS surface not only kept the potentials of proliferation and multi-differentiation of hMSCs, but also increased the viability of hMSCs.

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4

Abdul Samad, Yarjan, Yuanqing Li, and Kin liao. "A Novel Graphene Foam for Low and High Strains and Pressure Sensing Applications." MRS Advances 1, no. 1 (2016): 27–32. http://dx.doi.org/10.1557/adv.2016.20.

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ABSTRACTWe are reporting the formation of free-standing graphene foam (GF) via a novel two-step process, in which a polyurethane (PU) foam is first dip-coated with graphene oxide (GO) and subsequently the dried GO-coated-PU is heated in nitrogen atmosphere at 1000°C. During the pyrolysis of the GO-coated-PU, GO is reduced to GF whereas PU is simultaneously decomposed and released completely as volatiles in a step wise mass-loss mechanism. Morphology of the formed GF conforms to that of the pure PU foam as indicated by the scanning electronic micrographs. Polydimethylsiloxane (PDMS) was successfully infiltrated inside the GF to form flexible and stretch-able conductors. The GF-PDMS composite was tested for it’s pressure and strain sensing capabilities. It is shown that a 30% compressive strain changes resistance of the GF-PDMS composite to about 800% of it’s original value. Since density of the formed GF is tunable, therefore, the pressure/strain sensivity of the GF-PDMS composite is also tunable.

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5

Wahyuningsih, Sayekti, Rochmad E. Cahyono, and Fitri N. Aini. "Preparation Titanium Dioxide Combined Hydrophobic Polymer with Photocatalytic Self-Cleaning Properties." Bulletin of Chemical Reaction Engineering & Catalysis 15, no. 3 (December 10, 2020): 874–84. http://dx.doi.org/10.9767/bcrec.15.3.9225.874-884.

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Titanium dioxide (TiO2) and hydrophobic of TiO2/PDMS (PDMS = polydimethylsiloxane) have been prepared as photocatalytic self-cleaning materials. Synthesis of TiO2 was carried out using the sol-gel method with titanium(IV) isopropoxide (TTIP) as a precursor and acetic acid as a solvent at a temperature of about 10–15 °C, while the synthesis of hydrophobic of TiO2/PDMS composites was carried out by a sonication method under ethanol solution. The results of XRD analysis of synthesized TiO2 showed that TiO2 was anatase phase. The glass-coated TiO2/PDMS were prepared by dip-coating under an ultrasonication bath. TiO2/PDMS composites at a ratio of TiO2/PDMS (1) on the glass plate showed hydrophobic properties, as evidenced by the contact angle of 104° before irradiation and the contact angle of 99.7° after irradiation. The synthesized titanium dioxide has irregular spherical morphology. The increase in PDMS content was correlated with an increase in the roughness of TiO2. PDMS not only acts as low surface energy but also binds TiO2. The hydrophobic behavior of PDMS creates TiO2/PDMS repel each other, gain irregular agglomeration structures. Beside having optimum contact angle, glass-coated TiO2/PDMS (1) is the best composition for degradation of methylene blue in 69.68% for 20 minutes irradiation. Copyright © 2020 BCREC Group. All rights reserved

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6

Zhang, Chunmei, Tianliang Zhai, Chao Zhan, Qiuping Fu, and Chao Ma. "Actuation Behavior of Multilayer Graphene Nanosheets/Polydimethylsiloxane Composite Films." Polymers 10, no. 11 (November 9, 2018): 1243. http://dx.doi.org/10.3390/polym10111243.

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The graphene nanosheets (GNS)/polydimethylsiloxane (PDMS) composite films with out-of-plane dielectric actuation behavior were prepared through a layer-by-layer spin coating process. The GNS-PDMS/PDMS composite films with 1~3 layers of GNS-PDMS films were spin coated on top of the PDMS film. The dielectric, mechanical, and electromechanical actuation properties of the composite films were investigated. The dielectric constant of the GNS-PDMS3/PDMS composite film at 1 kHz is 5.52, which is 1.7 times that of the GNS-PDMS1/PDMS composite film. The actuated displacement of the GNS-PDMS/PDMS composite films is greatly enhanced by increasing the number of GNS-PDMS layers. This study provides a novel alternative approach for fabricating high-performance actuators with out-of-plane actuation behavior.

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7

Zhang, Jingran, Yongda Yan, Peng Miao, and Jianxiong Cai. "Fabrication of gold-coated PDMS surfaces with arrayed triangular micro/nanopyramids for use as SERS substrates." Beilstein Journal of Nanotechnology 8 (November 1, 2017): 2271–82. http://dx.doi.org/10.3762/bjnano.8.227.

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Using the tip-based continuous indentation process, arrays of three-dimensional pyramidal cavities have been successfully machined on a copper template and the structures were successfully transferred to a polydimethylsiloxane (PDMS) surface using a reverse nanoimprinting approach. The structured PDMS surface is coated with a thin Au film, and the final substrate is demonstrated as a surface-enhanced Raman spectroscopy (SERS) substrate. Rhodamine 6G (R6G) was used as a probe molecule in the present study to confirm the SERS measurements. Arrays of micro/nanostructures of different dimensions were formed by the overlap of pyramidal cavities with different adjacent distances using the tip-based continuous indentation process. The effects of the reverse nanoimprinting process and coating process on the final topography of the structures are studied. The experimental results show that the Raman intensity of the Au-film-coated PDMS substrate is influenced by the topography of the micro/nanostructures and by the thickness of the Au film. The Raman intensity of 1362 cm−1 R6G peak on the structured Au-film-coated PDMS substrate is about 8 times higher than the SERS tests on a commercial substrate (Q-SERS). A SERS enhancement factor ranging from 7.5 × 105 to 6 × 106 was achieved using the structured Au-film-coated PDMS surface, and it was demonstrated that the method proposed in this paper is reliable, replicable, homogeneous and low-cost for the fabrication of SERS substrates.

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8

Yang, Rui, Yunyi Liang, Shu Hong, Shida Zuo, Yingji Wu, Jiangtao Shi, Liping Cai, et al. "Novel Low-Temperature Chemical Vapor Deposition of Hydrothermal Delignified Wood for Hydrophobic Property." Polymers 12, no. 8 (August 6, 2020): 1757. http://dx.doi.org/10.3390/polym12081757.

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As a hydrophilic material, wood is difficult to utilize for external applications due to the variable weather conditions. In this study, an efficient, facile, and low-cost method was developed to enhance the hydrophobicity of wood. By applying the low-temperature chemical vapor deposition (CVD) technology, the polydimethylsiloxane-coated wood (PDMS@wood) with hydrophobic surface was fabricated employing dichlorodimethylsilane as the CVD chemical resource. The result of water contact angle (i.e., 157.3°) revealed the hydrophobic behavior of the PDMS@wood. The microstructures of the wood samples were observed by scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) analysis verified PDMS successfully coated on wood surfaces. The chemical functional groups of the PDMS@wood were investigated by Fourier transform infrared (FT-IR) and Raman spectra. The thermogravimetric results indicated the enhanced thermal stability of the wood after PDMS coating. In addition, the stability test of PDMS@wood indicated that the hydrophobicity properties of the PDMS@wood samples were preserved after long-time storage (e.g., 30 days). The scratch test was carried out to examine the abrasion resistance of the hydrophobic coatings on PDMS@wood surface. It was suggested that low-temperature CVD process could be a successful approach for fabricating hydrophobic wood.

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9

Taşdemir, Muharrem, Fatih Şenaslan, and Ayhan Çelik. "Investigation of corrosion and thermal behavior of PU–PDMS-coated AISI 316L." e-Polymers 21, no. 1 (January 1, 2021): 355–65. http://dx.doi.org/10.1515/epoly-2021-0035.

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Abstract Polydimethylsiloxane (PDMS) is widely used from biomedical to industrial applications due to its nontoxic, hydrophobic, and transparent characteristics. PDMS has good thermal and adhesion properties; however, its mechanical properties are comparatively weak. Therefore, PDMS is blended with various polymers to effectively improve its mechanical properties. In this study, polyurethane (PU)–polydimethylsiloxane (PDMS) blended coatings of different concentrations were applied on the AISI 316L stainless steel surface. Their effects on corrosion and tribocorrosion properties were investigated in Ringer’s solutions. The blended polymer coatings were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The thermal properties of samples were examined by TGA and DSC. The surface images and cross-sectional were investigated using scanning electron microscopy (SEM). Tribocorrosion tests were carried out at open circuit potential (OCP). It was determined that hydrophobicity and thermal stability of polymer coating increased, while corrosion resistance slightly decreased with the increasing PDMS concentration in the polymer blended. The friction coefficient of blends decreased as the PU concentration increased. As a result, it was determined that the polymer-coated samples containing up to 50% PDMS prevented corrosive wear under the OCP wear test in Ringer’s solutions.

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10

Aulia, Rahmi Khairani, Mark W. Beatty, and Bobby Simetich. "Effect of Superhydrophobic Coating and Nanofiller Loading on Facial Elastomer Physical Properties." Materials 15, no. 20 (October 20, 2022): 7343. http://dx.doi.org/10.3390/ma15207343.

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Facial prosthetics are currently constructed of materials that are far from optimal; superior materials with a “skin-like” feel are required. In this study, the property changes brought about by the consecutive additions of hydrophobic- and uncoated nano-SiO2 to polydimethylsiloxane (PDMS) are assessed, and the alterations are compared with those observed for conventional submicron SiO2-filled materials. In sequence, 0%, 0.5%, 5%, 10%, and 15% by weight of each filler type were successively added to vinyl-terminated PDMS. Tensile, tear, Durometer hardness, translucency, and viscoelastic properties were assessed, and hardness and translucency were further measured after 3000 h of outdoor weathering. The results showed that 15% coated nano- SiO2-filled PDMS materials given the highest tensile strength, elastic modulus, storage modulus, loss modulus, tear strength, and durometer hardness (p < 0.05), whereas 15% submicron coated SiO2-filled materials displayed the highest failure strain and translucency parameter (p < 0.05). Only 10%- and 15%-filled submicron SiO2 PDMS materials were altered by outdoor weathering; nevertheless, the increases were assessed to be too small to be clinically perceptible. As increased filler levels provided protection against solar radiation, heat, and moisture, only unfilled and 0.5%-filled PDMS formulations discolored from weathering. 15%-filled superhydrophobic-coated nano- SiO2-filled PDMS was found to produce the strongest, most tear-resistant, and least translucent materials, but it also produced materials with limited stretchability and high hardness, which were regarded to be downsides for creating a “skin-like” feel.

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Lo, Tien N. H., Ha Soo Hwang, and In Park. "Icephobicity of Hierarchically Rough Aluminum Surfaces Sequentially Coated with Fluoroalkyl and PDMS Alkoxysilanes." Polymers 15, no. 4 (February 13, 2023): 932. http://dx.doi.org/10.3390/polym15040932.

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Superhydrophobic surfaces fabricated by grafting 1H,1H,2H,2H-heptadecafluorodecyl trimethoxysilane (FD-TMS) and polydimethylsiloxane triethoxysilane (PDMS-TES) onto a nano-micro hierarchical aluminum (Al) surface are considered to possess substantial anti-icing functionality, with delayed freezing and low ice-adhesion strength (IAS). Verifying the impacts of PDMS and the synergism of PDMS and FD on the anti-icing performance is the goal of this study. Roughness, one of the prerequisites for superhydrophobicity, was obtained by etching Al substrates in aqueous HCl, followed by immersion in boiling water. FD-TMS and PDMS-TES were then coated on the rough Al substrates layer by layer; a congener coated with a single layer was also prepared for comparison. The FD-PDMS1.92 (1.92 wt.%) coating, in which FD-TMS and PDMS-TES were used as primary and secondary coating materials, respectively, exhibited superior icephobicity, with the lowest IAS of 28 kPa under extremely condensing weather conditions (−20 °C and 70% relative humidity, RH) and the longest freezing delay time of 230 min (at −18 °C). These features are attributed to the incorporation of a dense coating layer with a low-surface-tension FD and the high mobility of PDMS, which lowered the contact area and interaction between the ice and substrate. The substrate coated with FD-PDMS1.92 exhibited improved durability with an IAS of 63 kPa after 40 icing/melting cycles, which is far less than that achieved with the FD single-layer coating.

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12

Ning, Xiangping, Jingyi Yang, Chun Liu Zhao, and Chi Chiu Chan. "PDMS-coated fiber volatile organic compounds sensors." Applied Optics 55, no. 13 (April 27, 2016): 3543. http://dx.doi.org/10.1364/ao.55.003543.

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13

Cho, Woong, Yong Jun Ko, Yoo Min Ahn, Joon Yong Yoon, and Nahm Gyoo Cho. "Surface Modification Effect of Wettability on the Performance of PDMS-Based Valveless Micropump." Key Engineering Materials 326-328 (December 2006): 297–300. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.297.

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Experimental investigation and numerical simulation on the effect of surface wettability on the performance of a polydimethylsiloxane (PDMS) based diffuser micropump are presented. A valveless micro membrane pump with piezoelectric actuation has been examined. Using a replica molding technique, the valveless micropump was made of PDMS on a Pyrex glass substrate. A thin piezoelectric (PZT) disc was used as an actuator. Poly vinyl alcohol (PVA) and octadecyltrichlorosilane (OTS) coatings, which make the coated surface hydrophilic and hydrophobic, respectively, were used to modify the surface wettability inside the pump. In our experiments, the contact angle of the PDMS surface changed from 96.6 o to 29.1 o and 99.6 o by PVA and OTS coatings, respectively, and the contact angle of glass changed from 33.2 o to 17.5 o and 141.8 o. A self-priming process was numerically simulated in a diffuser element using a computational fluid dynamics program (CFD-ACE+). The results show that fewer gas bubbles were created in the hydrophilic coated pump than in the hydrophobic coated one as time progressed. This agrees well with experimental observations. Steady-state flow rates of the micropump were measured. Compared to the non-coated pump, the flow rate increased slightly with the hydrophobic coating but decreased with the hydrophilic coating. We determine that surface wettability significantly affects the performance of a PDMS-based micropump.

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14

Sridharan, Arati, Vikram Kodibagkar, and Jit Muthuswamy. "Penetrating Microindentation of Hyper-soft, Conductive Silicone Neural Interfaces in Vivo Reveals Significantly Lower Mechanical Stresses." MRS Advances 4, no. 46-47 (2019): 2551–58. http://dx.doi.org/10.1557/adv.2019.356.

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ABSTRACTThere is growing evidence that minimizing the mechanical mismatch between neural implants and brain tissue mitigates inflammatory, biological responses at the interface under long-term implant conditions. The goal of this study is to develop a brain-like soft, conductive neural interface and use an improvised, penetrating microindentation technique reported by us earlier to quantitatively assess the (a) elastic modulus of the neural interface after implantation, (b) mechanical stresses during penetration of the probe, and (c) periodic stresses at steady-state due to tissue micromotion around the probe. We fabricated poly- dimethylsiloxane (PDMS) matrices with multi-walled carbon nanotubes (MWCNTs) using two distinct but carefully calibrated cross-linking ratios, resulting in hard (elastic modulus∼484 kPa) or soft, brain-like (elastic modulus∼5.7 kPa) matrices, the latter being at least 2 orders of magnitude softer than soft neural interfaces reported so far. Subsequent loading of the hard and soft silicone based matrices with (100% w/w) low-molecular weight PDMS siloxanes resulted in further decrease in the elastic modulus of both matrices. Carbon probes with soft PDMS coating show significantly less maximum axial forces (-587 ± 51.5 µN) imposed on the brain than hard PDMS coated probes (-1,253 ± 252 µN) during and after insertion. Steady-state, physiological micromotion related stresses were also significantly less for soft- PDMS coated probes (55.5 ± 17.4 Pa) compared to hard-PDMS coated probes (141.0 ± 21.7 Pa). The penetrating microindentation technique is valuable to quantitatively assess the mechanical properties of neural interfaces in both acute and chronic conditions.

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15

Skwira, Adrianna, Adrian Szewczyk, and Magdalena Prokopowicz. "The Effect of Polydimethylsiloxane-Ethylcellulose Coating Blends on the Surface Characterization and Drug Release of Ciprofloxacin-Loaded Mesoporous Silica." Polymers 11, no. 9 (September 4, 2019): 1450. http://dx.doi.org/10.3390/polym11091450.

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In this study, we obtained novel solid films composed of ciprofloxacin-loaded mesoporous silica materials (CIP-loaded MCM-41) and polymer coating blends. Polymer coating blends were composed of ethylcellulose (EC) with various levels of polydimethylsiloxane (PDMS, 0, 1, 2% (v/v)). The solid films were prepared via the solvent-evaporation molding method and characterized by using scanning electron microscopy (SEM), optical profilometry, and wettability analyses. The solid-state of CIP present in the solid films was studied using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The release profiles of CIP were examined as a function of PDMS content in solid films. The surface morphology analysis of solid films indicated the progressive increase in surface heterogeneity and roughness with increasing PDMS content. The contact angle study confirmed the hydrophobicity of all solid films and significant impact of both PDMS and CIP-loaded MCM-41 on surface wettability. DSC and XRD analysis confirmed the presence of amorphous/semi-crystalline CIP in solid films. The Fickian diffusion-controlled drug release was observed for the CIP-loaded MCM-41 coated with PDMS-free polymer blend, whereas zero-order drug release was noticed for the CIP-loaded MCM-41 coated with polymer blends enriched with PDMS. Both the release rate and initial burst of CIP decreased with increasing PDMS content.

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Chong, Kok Chung, Soon Onn Lai, Hui San Thiam, Shee Keat Mah, Woei Jye Lau, and Ahmad Fauzi Ismail. "Performance Evaluation of PDMS or PEBAX-Coated Polyetherimide Membrane for Oxygen/Nitrogen Separation." Sains Malaysiana 50, no. 11 (November 30, 2021): 3395–404. http://dx.doi.org/10.17576/jsm-2021-5011-23.

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Since the industrial revolution era, the Earth was suffering from serious air pollution. Millions of people are now suffering from indoor air pollution related diseases, especially in the industrialized countries such as China. One method to improve the indoor air quality is by oxygen enhancement. Membrane technology has been a key research over the past decades due to its low energy usage, minimum chemical consumption as well as small setting up layout. In this study, polyetherimide (PEI) membranes coated with polydimethylsiloxane (PDMS) or poly(ether block amide) (PEBAX) at different concentration (1, 3 or 5 wt%) were used to evaluate the oxygen/nitrogen gas separation. Prior to the gas permeation study, the membranes were characterized using scanning electron microscope (SEM) for morphology observation and surface elemental analysis by energy dispersive X-ray spectroscope (EDX). The morphology of the self-fabricated PEI membranes is composed of a thin and dense structure supported by the finger-like structure. The results obtained from oxygen/nitrogen separation studies shows membrane coated with 3 wt% PDMS yield a good separation results, exhibiting an improvement of oxygen and nitrogen permeance by 28.2% and 24.9%, selectivity by 10.4% (up to 5.08) relative to the base PEI membrane. Meanwhile, the 3 wt% PEBAX-coated PEI membrane only achieved selectivity of 3.56. The PDMS-coated PEI membrane yield a better separation performance attributed to the fact that PDMS coating on the hollow fiber membrane improve the surface morphology by reducing the defects.

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Huda, Miftakhul, You Yin, and Sumio Hosaka. "Self-Assembled Nanodot Fabrication by Using Diblock Copolymer." Key Engineering Materials 459 (December 2010): 120–23. http://dx.doi.org/10.4028/www.scientific.net/kem.459.120.

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In this study, we investigate self-assembled large-area nanodot fabrication on a silicon substrate using poly(styrene)-poly(dimethyl-siloxane) (PS-PDMS) for the application to quantum dot solar cell. By optimizing the PS-PDMS concentration by 2% and the volume of PS-PDMS solutions by 20 μL/cm2 dropped to silicon substrate, nanodots with a pitch size of 33 nm and a diameter of 23 nm are achieved with the molecular weight of 30,000-7,500. It is found that the dropped volume of PS-PDMS solution correlated to the thickness of spin-coated PS-PDMS layer has a great effect on the size and the pattern morphology.

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Dabaghi, Mohammadhossein, Shadi Shahriari, Neda Saraei, Kevin Da, Abiram Chandiramohan, Ponnambalam Ravi Selvaganapathy, and Jeremy A. Hirota. "Surface Modification of PDMS-Based Microfluidic Devices with Collagen Using Polydopamine as a Spacer to Enhance Primary Human Bronchial Epithelial Cell Adhesion." Micromachines 12, no. 2 (January 26, 2021): 132. http://dx.doi.org/10.3390/mi12020132.

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Polydimethylsiloxane (PDMS) is a silicone-based synthetic material used in various biomedical applications due to its properties, including transparency, flexibility, permeability to gases, and ease of use. Though PDMS facilitates and assists the fabrication of complicated geometries at micro- and nano-scales, it does not optimally interact with cells for adherence and proliferation. Various strategies have been proposed to render PDMS to enhance cell attachment. The majority of these surface modification techniques have been offered for a static cell culture system. However, dynamic cell culture systems such as organ-on-a-chip devices are demanding platforms that recapitulate a living tissue microenvironment’s complexity. In organ-on-a-chip platforms, PDMS surfaces are usually coated by extracellular matrix (ECM) proteins, which occur as a result of a physical and weak bonding between PDMS and ECM proteins, and this binding can be degraded when it is exposed to shear stresses. This work reports static and dynamic coating methods to covalently bind collagen within a PDMS-based microfluidic device using polydopamine (PDA). These coating methods were evaluated using water contact angle measurement and atomic force microscopy (AFM) to optimize coating conditions. The biocompatibility of collagen-coated PDMS devices was assessed by culturing primary human bronchial epithelial cells (HBECs) in microfluidic devices. It was shown that both PDA coating methods could be used to bind collagen, thereby improving cell adhesion (approximately three times higher) without showing any discernible difference in cell attachment between these two methods. These results suggested that such a surface modification can help coat extracellular matrix protein onto PDMS-based microfluidic devices.

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Cao, Kun, Xi Huang, and Jie Pan. "Application of Superhydrophobic Mesh Coated by PDMS/TiO2 Nanocomposites for Oil/Water Separation." Polymers 14, no. 24 (December 12, 2022): 5431. http://dx.doi.org/10.3390/polym14245431.

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Superhydrophobic materials have recently attracted great interest from both academia and industry due to their promising applications in self-cleaning, oil–water separation, etc. Here, we developed a facile method to prepare hybrid PDMS/TiO2 fiber for superhydrophobic coatings. TiO2 could be uniformly distributed into PDMS, forming a hierarchical micro/nano structure on the surface of the substrate. The contact angle of the superhydrophobic coating could reach as high as 155°. The superhydrophobic coating possessed good self-cleaning performance, corrosion resistance, and durability. It was found that gravity-driven oil–water separation was achieved using stainless steel mesh coated with the PDMS/TiO2 coating. More importantly, the coated filter paper could not only separate oil and pure water but also corrosive solutions, including the salt, acid, and alkali solution.

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Xu, Liyun, Kaifang Xie, Yuegang Liu, and Chengjiao Zhang. "Stable super-hydrophobic and comfort PDMS-coated polyester fabric." e-Polymers 21, no. 1 (January 1, 2021): 654–61. http://dx.doi.org/10.1515/epoly-2021-0059.

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Abstract Super-hydrophobic fabrics have shown great potential during the last decade owing to their novel functions and enormous potential for diver’s applications. Surface textures and low surface energy coatings are the keys to high water repellency. However, the toxicity of nanomaterials, long perfluorinated side-chain polymers, and the fragile of micro/nano-texture lead to the super-hydrophobic surfaces are confined to small-scale uses. Thus, in this article, a stable polydimethylsiloxane (PDMS)-coated super-hydrophobic poly(ethylene terephthalate) (PET) fabric (PDMS-g-PET) is manufactured via dip-plasma crosslinking without changing the wearing comfort. Benefiting from the special wrinkled structure of PDMS film, the coating is durable enough against physical abrasion and repeated washing damage, which is suffered from 100 cycles of washing or 500 abrasion cycles, and the water contact angle is still above 150°. This study promotes the way for the development of environmentally friendly, safe, and cost-efficient for designing durable superhydrophobic coatings for various practical applications.

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Kemkemer, Ralf, Zhang Zenghao, Yang Linxiao, Kiriaki Athanasopulu, Kerstin Frey, Zhishan Cui, Haijia Su, and Liu Luo. "Surface modification of Polydimethylsiloxane by hydrogels for microfluidic applications." Current Directions in Biomedical Engineering 5, no. 1 (September 1, 2019): 93–96. http://dx.doi.org/10.1515/cdbme-2019-0024.

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AbstractIn vitro, hydrogel-based ECMs for functionalizing surfaces of various material have played an essential role in mimicking native tissue matrix. Polydimethylsiloxane (PDMS) is widely used to build microfluidic or organ-on-chip devices compatible with cells due to its easy handling in cast replication. Despite such advantages, the limitation of PDMS is its hydrophobic surface property. To improve wettability of PDMS-based devices, alginate, a naturally derived polysaccharide, was covalently bound to the PDMS surface. This alginate then crosslinked further hydrogel onto the PDMS surface in desired layer thickness. Hydrogel-modified PDMS was used for coating a topography chip system and in vitro investigation of cell growth on the surfaces. Moreover, such hydrophilic hydrogel-coated PDMS is utilized in a microfluidic device to prevent unspecific absorption of organic solutions. Hence, in both exemplary studies, PDMS surface properties were modified leading to improved devices.

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22

Nguyen, Duc Cuong, Trung Tuyen Bui, Yeong Beom Cho, and Yong Shin Kim. "Highly Hydrophobic Polydimethylsiloxane-Coated Expanded Vermiculite Sorbents for Selective Oil Removal from Water." Nanomaterials 11, no. 2 (February 2, 2021): 367. http://dx.doi.org/10.3390/nano11020367.

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Naturally abundant vermiculite clay was expanded by using an aqueous solution of H2O2 and its surface was modified with ultra-thin polydimethylsiloxane (PDMS) using facile thermal vapor deposition to prepare an ecologically friendly, low-cost oil sorbent that plays an important role in oil spillage remediation. The resulting PDMS-coated expanded vermiculite (eVMT@PDMS) particles exhibited adequate hydrophobicity and oleophilicity for oil/water separation, with numerous conical slit pores (a size of 0.1–100 μm) providing a great sorption capacity and an efficient capillarity-driven flow pathway for oil collection. Simply with using a physically-packed eVMT@PDMS tube (or pouch), selective oil removals were demonstrated above and beneath the surface of the water. Furthermore, these sorbents were successfully integrated and then applied to the advanced oil-collecting devices such as a barrel-shaped oil skimmer and a self-primed oil pump.

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23

Yan, Xingzhen, Bo Li, Kaian Song, Fan Yang, Yanjie Wang, Chao Wang, Yaodan Chi, and Xiaotian Yang. "Ultra-thin foldable transparent electrodes composed of stacked silver nanowires embedded in polydimethylsiloxane." Materials Research Express 9, no. 1 (January 1, 2022): 015006. http://dx.doi.org/10.1088/2053-1591/ac493f.

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Abstract We have prepared an ultra-thin flexible transparent conductive electrode with high folding endurance composed of randomly arranged silver nanowires (AgNWs) embedded in polydimethylsiloxane (PDMS). A simple preparation method was performed to connect a glass substrate coated with a AgNW network and a glass substrate coated with PDMS. The glass substrate was then removed after the PDMS solidified, and the AgNW–PDMS composite film was peeled off. Moreover, the problem of the high contact resistance caused by the random arrangement of AgNWs was solved by the local joule heat generated by applying voltage to both sides of the AgNW–PDMS composite structure to weld the overlapping AgNWs. The sheet resistance (R s) of AgNW–PDMS composite films with different AgNW deposition concentrations decreased by 46.4%–75.8% through this electro-sintering treatment. The embedded structure of the AgNW–PDMS composite ensures better voltage resistance and environmental stability under high temperature and humidity conditions compared with a AgNW network attached to a glass substrate. Additionally, the substrate-free, excellent elasticity and high resilience characteristics resulted in the R s value of the same composite electrode only increasing by 2.9 ohm sq−1 after folding four times. The advantage of the metal thermal conductivity makes the joule heat generated by electric injection rapidly diffuse and dissipate in the AgNW-based transparent heater with faster response time and smaller voltage drive than indium tin oxide.

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24

Yamashita, Tomohisa, and Tatsuya Muramoto. "Reducing the channel diameter of polydimethylsiloxane fluidic chips made by a 3D-printed sacrificial template and their application for flow-injection analysis." Analytical Sciences 38, no. 3 (February 15, 2022): 583–89. http://dx.doi.org/10.1007/s44211-022-00070-1.

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AbstractFluidic chips have attracted considerable interest in recent years for their potential applications in analytical devices. Previously, we developed a method to fabricate polydimethylsiloxane (PDMS) fluidic chips via templates made using a low-priced commercial Fused Deposition Modeling (FDM) type 3D printer and polymer coatings. However, in general, methods using a template cannot form a flow channel thinner than the template thickness and the width. In this study, the inner wall of a PDMS fluidic chip was coated with PDMS to create a chip with a channel inner diameter smaller than a template. Then, by measuring the flow signal of methyl orange with a single line, the basic properties of the non-coated and coated chip were investigated. As a result, almost the same flow profile was obtained in non-coated and coated chips at the same linear velocity and the same sample injection length. By coating and narrowing the channel width, it is possible to save the amount of sample and carrier solution. Measuring hydrazine in water using a coated chip was also tried. The calibration curve indicated good linearity in the range of 1–6 ppm. However, a concentration point of 7 ppm deviated. The reason for this deviation was presumably due to inadequate mixing of the sample and reagent. By decreasing the flow rate, the calibration curve indicated good linearity in the range of 1–7 ppm. Graphical abstract

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25

Kim, Su Jin, Bumkyoo Choi, Kang Sup Kim, Woong Jin Bae, Sung Hoo Hong, Ji Youl Lee, Tae-Kon Hwang, and Sae Woong Kim. "The Potential Role of Polymethyl Methacrylate as a New Packaging Material for the Implantable Medical Device in the Bladder." BioMed Research International 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/852456.

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Polydimethylsiloxane (PDMS) is used in implantable medical devices; however, PDMS is not a completely biocompatible material for electronic medical devices in the bladder. To identify novel biocompatible materials for intravesical implanted medical devices, we evaluated the biocompatibility of polymethyl methacrylate (PMMA) by analyzing changes in the levels of macrophages, macrophage migratory inhibitory factor (MIF), and inflammatory cytokines in the bladder. A ball-shaped metal coated with PMMA or PDMS was implanted into the bladders of rats, and after intravesical implantation, the inflammatory changes induced by the foreign body reaction were evaluated. In the early period after implantation, increased macrophage activity and MIF in the urothelium of the bladder were observed. However, significantly decreased macrophage activity and MIF in the bladder were observed after implantation with PMMA- or PDMS-coated metal in the later period. In addition, significantly decreased inflammatory cytokines such as IL-1β, IL-6, and TNF-αwere observed with time. Based on these results, we suggest that MIF plays a role in the foreign body reaction and in the biocompatible packaging with PMMA for the implanted medical devices in the bladder.

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26

Xie, Han, Tong Cao, Alfredo Franco-Obregón, and Vinicius Rosa. "Graphene-Induced Osteogenic Differentiation Is Mediated by the Integrin/FAK Axis." International Journal of Molecular Sciences 20, no. 3 (January 29, 2019): 574. http://dx.doi.org/10.3390/ijms20030574.

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Graphene is capable of promoting osteogenesis without chemical induction. Nevertheless, the underlying mechanism(s) remain largely unknown. The objectives here were: (i) to assess whether graphene scaffolds are capable of supporting osteogenesis in vivo and; (ii) to ascertain the participation of the integrin/FAK mechanotransduction axis during the osteogenic differentiation induced by graphene. MSC-impregnated graphene scaffolds (n = 6) were implanted into immunocompromised mice (28 days). Alternatively, MSCs were seeded onto PDMS substrates (modulus of elasticity = 130, 830 and 1300 kPa) coated with a single monomolecular layer of graphene and cultured in basal medium (10 days). The ensuing expressions of FAK-p397, integrin, ROCK1, F-actin, Smad p1/5, RUNX2, OCN and OPN were evaluated by Western blot (n = 3). As controls, MSCs were plated onto uncoated PDMS in the presence of mechanotransduction inhibitors (echistatin, Y27632 and DMH1). MSC-impregnated graphene scaffolds exhibited positive immunoexpression of bone-related markers (RUNX2 and OPN) without the assistance of osteogenic inducers. In vitro, regardless of the stiffness of the underlying PDMS substrate, MSCs seeded onto graphene-coated PDMS substrates demonstrated higher expressions of all tested osteogenic and integrin/FAK proteins tested compared to MSCs seeded onto PDMS alone. Hence, graphene promotes osteogenesis via the activation of the mechanosensitive integrin/FAK axis.

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Joshi, Shivani, Antonie van Loon, Angel Savov, and Ronald Dekker. "Adhesion Improvement of Polyimide/PDMS Interface by Polyimide Surface Modification." MRS Advances 1, no. 1 (2016): 33–38. http://dx.doi.org/10.1557/adv.2016.56.

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ABSTRACTSilicon wafers coated with a 5μm thick layer of polyimide were treated with different surface modification techniques such as chemical adhesion promoters, oxygen plasma and an Ar+ sputter etch. After surface modification, the wafers were molded with a 1mm thick layer of PDMS. The adhesion of the PDMS was tested by peel testing and by using a Nordson DAGE wedge shear tester. It was found that commercially available chemical adhesion promoters and oxygen plasma treatment resulted in a very poor PI/PDMS adhesion, whereas the Ar+ sputter etch resulted in an adhesion so strong that the PDMS could not be delaminated from the PI surface without the failure of the material.

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28

Xu, Huaping, Alberto Gomez-Casado, Zhihua Liu, David N. Reinhoudt, Rob G. H. Lammertink, and Jurriaan Huskens. "Porous Multilayer-Coated PDMS Stamps for Protein Printing†." Langmuir 25, no. 24 (December 15, 2009): 13972–77. http://dx.doi.org/10.1021/la901797n.

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29

Bensalah, Fatma, Julien Pézard, Naoufel Haddour, Mohsen Erouel, François Buret, and Kamel Khirouni. "Carbon Nano-Fiber/PDMS Composite Used as Corrosion-Resistant Coating for Copper Anodes in Microbial Fuel Cells." Nanomaterials 11, no. 11 (November 21, 2021): 3144. http://dx.doi.org/10.3390/nano11113144.

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The development of high-performance anode materials is one of the greatest challenges for the practical implementation of Microbial Fuel Cell (MFC) technology. Copper (Cu) has a much higher electrical conductivity than carbon-based materials usually used as anodes in MFCs. However, it is an unsuitable anode material, in raw state, for MFC application due to its corrosion and its toxicity to microorganisms. In this paper, we report the development of a Cu anode material coated with a corrosion-resistant composite made of Polydimethylsiloxane (PDMS) doped with carbon nanofiber (CNF). The surface modification method was optimized for improving the interfacial electron transfer of Cu anodes for use in MFCs. Characterization of CNF-PDMS composites doped at different weight ratios demonstrated that the best electrical conductivity and electrochemical properties are obtained at 8% weight ratio of CNF/PDMS mixture. Electrochemical characterization showed that the corrosion rate of Cu electrode in acidified solution decreased from (17 ± 6) × 103 μm y−1 to 93 ± 23 μm y−1 after CNF-PDMS coating. The performance of Cu anodes coated with different layer thicknesses of CNF-PDMS (250 µm, 500 µm, and 1000 µm), was evaluated in MFC. The highest power density of 70 ± 8 mW m−2 obtained with 500 µm CNF-PDMS was about 8-times higher and more stable than that obtained through galvanic corrosion of unmodified Cu. Consequently, the followed process improves the performance of Cu anode for MFC applications.

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30

Glover, Justin D., and Jonathan T. Pham. "Capillary-driven indentation of a microparticle into a soft, oil-coated substrate." Soft Matter 16, no. 25 (2020): 5812–18. http://dx.doi.org/10.1039/d0sm00296h.

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Yang, Da Hyun, Sangyong Jung, Jae Young Kim, and Nae Yoon Lee. "Fabrication of a Cell-Friendly Poly(dimethylsiloxane) Culture Surface via Polydopamine Coating." Micromachines 13, no. 7 (July 15, 2022): 1122. http://dx.doi.org/10.3390/mi13071122.

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In this study, we fabricated a poly(dimethylsiloxane) (PDMS) surface coated with polydopamine (PDA) to enhance cell adhesion. PDA is well known for improving surface adhesion on various surfaces due to the abundant reactions enabled by the phenyl, amine, and catechol groups contained within it. To confirm the successful surface coating with PDA, the water contact angle and X-ray photoelectron spectroscopy were analyzed. Human umbilical vein endothelial cells (HUVECs) and human-bone-marrow-derived mesenchymal stem cells (MSCs) were cultured on the PDA-coated PDMS surface to evaluate potential improvements in cell adhesion and proliferation. HUVECs were also cultured inside a cylindrical PDMS microchannel, which was constructed to mimic a human blood vessel, and their growth and performance were compared to those of cells grown inside a rectangular microchannel. This study provides a helpful perspective for building a platform that mimics in vivo environments in a more realistic manner.

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Basiron, Norfatehah, Srimala Sreekantan, Khairul Arifah Saharudin, Zainal Arifin Ahmad, and Vignesh Kumaravel. "Improved Adhesion of Nonfluorinated ZnO Nanotriangle Superhydrophobic Layer on Glass Surface by Spray-Coating Method." Journal of Nanomaterials 2018 (October 21, 2018): 1–11. http://dx.doi.org/10.1155/2018/7824827.

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In this present work, a superhydrophobic glass surface comprising zinc oxide nanotriangles (ZnO-nt) and nontoxic silylating agent was developed via a cost-effective spray-coating technology. ZnO-nt was synthesized by a hydrothermal method. Poly(dimethylsiloxane) (PDMS) and dimethyldiethoxysilane (DMDEOS) were used as nontoxic (nonfluoro) silylating agents. The morphology and crystallinity of ZnO-nt were studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. ZnO-nt with polymeric silane (PDMS) exhibited maximum wettability as compared to nonpolymeric silane (DMDEOS). The water contact angle (WCA), sliding angle (SA), and surface roughness of ZnO-nt/PDMS-coated glass substrate under UV treatment were 165 ± 1°, 3 ± 1°, and 791 nm, respectively. The WCA of ZnO-nt/PDMS was higher (165°) than that of commercial ZnO/PDMS (ZnO-C/PDMS). ZnO-nt/PDMS was strongly attached to the glass substrate with good stability and adhesion. The reasons for improved hydrophobicity, adhesion, and mechanism of hierarchical microstructure formation on the glass substrate were explained in detail. PDMS was attached to the glass substrate via hydrogen bonds from solvated zinc acetate.

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Pham, Hoang Lan, Da Hyun Yang, Woo Ri Chae, Jong Hyeok Jung, Thi Xoan Hoang, Nae Yoon Lee, and Jae Young Kim. "PDMS Micropatterns Coated with PDA and RGD Induce a Regulatory Macrophage-like Phenotype." Micromachines 14, no. 3 (March 17, 2023): 673. http://dx.doi.org/10.3390/mi14030673.

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Regulatory macrophages (Mreg) are a special cell type that present a potential therapeutic strategy for various inflammatory diseases. In vitro, Mreg generation mainly takes 7–10 days of treatment with chemicals, including cytokines. In the present study, we established a new approach for Mreg generation using a three-dimensional (3D) micropatterned polydimethylsiloxane (PDMS) surface coated with a natural biopolymer adhesive polydopamine (PDA) and the common cell adhesion peptide motif arginylglycylaspartic acid (RGD). The 3D PDMS surfaces were fabricated by photolithography and soft lithography techniques and were subsequently coated with an RGD+PDA mixture to form a surface that facilitates cell adhesion. Human monocytes (THP-1 cells) were cultured on different types of 2D or 3D micropatterns for four days, and the cell morphology, elongation, and Mreg marker expression were assessed using microscopic and flow cytometric analyses. The cells grown on the PDA+RGD-coated 3D micropatterns (20-µm width/20-µm space) exhibited the most elongated morphology and strongest expression levels of Mreg markers, such as CD163, CD206, CD209, CD274, MER-TK, TREM2, and DHRS9. The present study demonstrated that PDA+RGD-coated 3D PDMS micropatterns successfully induced Mreg-like cells from THP-1 cells within four days without the use of cytokines, suggesting a time- and cost-effective method to generate Mreg-like cells in vitro.

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34

Song, Yuexiao, Feng Xin, and Yongsheng Xu. "Catalytic exchange of hydrogen isotopes intensified by two-phase stratified flow in wettability designable microchannels." Lab on a Chip 20, no. 12 (2020): 2154–65. http://dx.doi.org/10.1039/d0lc00250j.

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35

Howley, Rhona, B. D. MacCraith, Kieran O'Dwyer, Hugh Masterson, P. Kirwan, and Peter McLoughlin. "Determination of Hydrocarbons Using Sapphire Fibers Coated with Poly(Dimethylsiloxane)." Applied Spectroscopy 57, no. 4 (April 2003): 400–406. http://dx.doi.org/10.1366/00037020360625934.

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A poly(dimethylsiloxane) (PDMS) coated sapphire fiber has been investigated as a sensor for hydrocarbons (HCs) in the mid-infrared region around 3000 cm−1. In order to optimize and predict sensor response, the diffusion behavior of the analytes into the PDMS preconcentration medium has been examined. A diffusion model based on Fickian diffusion was used to quantify diffusion. The model incorporated such factors as film thickness, refractive index of the polymer and the fiber core, and principal wavelength at which the analyte absorbs. A range of hydrocarbons, from hexane to pentadecane, was analyzed at 2930 cm−1 using both fiber-coupled Fourier transform infrared spectroscopy and a modular prototype system. Diffusion coefficients were determined for these compounds and diffusion behavior examined and related to factors such as analyte polarity and molecular size. The diffusion coefficients were found to range from 6.41 × 10−11 ± 5 × 10−12 to 5.25 × 10−11 ± 9 × 10−13 cm2 s−1 for hexane and pentadecane into a 2.9 μm PDMS film, respectively. The diffusion model was also used to examine the effect of changing system parameters such as film thickness in order to characterize sensor response.

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Oh, Ji Hyun, and Chung Hee Park. "The Effect of Fiber Type and Yarn Diameter on Superhydrophobicity, Self-Cleaning Property, and Water Spray Resistance." Polymers 13, no. 5 (March 7, 2021): 817. http://dx.doi.org/10.3390/polym13050817.

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In this study, we proved that micro/micro hierarchical structures are enough to achieve a superhydrophobic surface using polydimethylsiloxane (PDMS) dip-coating. Furthermore, the effect of fiber type and yarn diameter on superhydrophobicity and water spray resistance was investigated. Polyester fabrics with two types of fibers (staple fabric and filament) and three types of yarn diameters (177D, 314D, and 475D) were used. The changes in the surface properties and chemical composition were investigated. Static contact angles and shedding angles were measured for superhydrophobicity, and the self-cleaning test was conducted. Water spray repellency was also tested, as well as the water vapor transmission rate and air permeability. The PDMS-coated staple fabric showed better superhydrophobicity and oleophobicity than the PDMS-coated filament fabric, while the filament fabric showed good self-cleaning property and higher water spray repellency level. When the yarn diameter increased, the fabrics needed higher PDMS concentrations and longer coating durations for uniform coating. The water vapor transmission rate and air permeability did not change significantly after coating. Therefore, the superhydrophobic micro/micro hierarchical fabrics produced using the simple method of this study are more practical and have great potential for mass production than other superhydrophobic textiles prepared using the chemical methods.

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Razafiarison, Tojo, Claude N. Holenstein, Tino Stauber, Milan Jovic, Edward Vertudes, Marko Loparic, Maciej Kawecki, Laetitia Bernard, Unai Silvan, and Jess G. Snedeker. "Biomaterial surface energy-driven ligand assembly strongly regulates stem cell mechanosensitivity and fate on very soft substrates." Proceedings of the National Academy of Sciences 115, no. 18 (April 16, 2018): 4631–36. http://dx.doi.org/10.1073/pnas.1704543115.

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Although mechanisms of cell–material interaction and cellular mechanotransduction are increasingly understood, the mechanical insensitivity of mesenchymal cells to certain soft amorphous biomaterial substrates has remained largely unexplained. We reveal that surface energy-driven supramolecular ligand assembly can regulate mesenchymal stem cell (MSC) sensing of substrate mechanical compliance and subsequent cell fate. Human MSCs were cultured on collagen-coated hydrophobic polydimethylsiloxane (PDMS) and hydrophilic polyethylene-oxide-PDMS (PEO-PDMS) of a range of stiffnesses. Although cell contractility was similarly diminished on soft substrates of both types, cell spreading and osteogenic differentiation occurred only on soft PDMS and not hydrophilic PEO-PDMS (elastic modulus <1 kPa). Substrate surface energy yields distinct ligand topologies with accordingly distinct profiles of recruited transmembrane cell receptors and related focal adhesion signaling. These differences did not differentially regulate Rho-associated kinase activity, but nonetheless regulated both cell spreading and downstream differentiation.

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38

Chen, Yong, Feng Li, Wei Cao, and Taohai Li. "Preparation of recyclable CdS photocatalytic and superhydrophobic films with photostability by using a screen-printing technique." Journal of Materials Chemistry A 3, no. 33 (2015): 16934–40. http://dx.doi.org/10.1039/c5ta04065e.

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39

Jang, Yeongseok, Hyojae Kim, Jinmu Jung, and Jonghyun Oh. "Controlled Thin Polydimethylsiloxane Membrane with Small and Large Micropores for Enhanced Attachment and Detachment of the Cell Sheet." Membranes 12, no. 7 (July 3, 2022): 688. http://dx.doi.org/10.3390/membranes12070688.

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Polydimethylsiloxane (PDMS) membranes can allow the precise control of well-defined micropore generation. A PDMS solution was mixed with a Rushton impeller to generate a large number of microbubbles. The mixed solution was spin-coated on silicon wafer to control the membrane thickness. The microbubbles caused the generation of a large number of small and large micropores in the PDMS membranes with decreased membrane thickness. The morphology of the thinner porous PDMS membrane induced higher values of roughness, Young’s modulus, contact angle, and air permeability. At day 7, the viability of cells on the porous PDMS membranes fabricated at the spin-coating speed of 5000 rpm was the highest (more than 98%) due to their internal networking structure and surface properties. These characteristics closely correlated with the increased formation of actin stress fibers and migration of keratinocyte cells, resulting in enhanced physical connection of actin stress fibers of neighboring cells throughout the discontinuous adherent junctions. The intact detachment of a cell sheet attached to a porous PDMS membrane was demonstrated. Therefore, PDMS has a great potential for enhancing the formation of cell sheets in regenerative medicine.

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40

Tian, Ning, Yuan Gao, Jiafei Wu, Suqing Luo, and Wei Dai. "Water-resistant HKUST-1 functionalized with polydimethylsiloxane for efficient rubidium ion capture." New Journal of Chemistry 43, no. 39 (2019): 15539–47. http://dx.doi.org/10.1039/c9nj03632f.

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41

Guo, Huihui, Liang Lou, Xiangdong Chen, and Chengkuo Lee. "PDMS-Coated Piezoresistive NEMS Diaphragm for Chloroform Vapor Detection." IEEE Electron Device Letters 33, no. 7 (July 2012): 1078–80. http://dx.doi.org/10.1109/led.2012.2195152.

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42

Sung Hwan Cho, J. Godin, and Yu-Hwa Lo. "Optofluidic Waveguides in Teflon AF-Coated PDMS Microfluidic Channels." IEEE Photonics Technology Letters 21, no. 15 (August 2009): 1057–59. http://dx.doi.org/10.1109/lpt.2009.2022276.

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43

Lu, Gang, Hai Li, and Hua Zhang. "Nanoparticle-coated PDMS elastomers for enhancement of Raman scattering." Chemical Communications 47, no. 30 (2011): 8560. http://dx.doi.org/10.1039/c1cc12027a.

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44

Park, Jaesung, Hee Wook Yoon, Donald R. Paul, and Benny D. Freeman. "Gas transport properties of PDMS-coated reverse osmosis membranes." Journal of Membrane Science 604 (June 2020): 118009. http://dx.doi.org/10.1016/j.memsci.2020.118009.

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45

Ko, Yeong Hwan, Goli Nagaraju, and Jae Su Yu. "Multi-stacked PDMS-based triboelectric generators with conductive textile for efficient energy harvesting." RSC Advances 5, no. 9 (2015): 6437–42. http://dx.doi.org/10.1039/c4ra15310c.

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Facile fabrication of multi-stacked triboelectric generators with the PDMS coated CT and bare CT, and enhancement of output performance due to the increased friction area for triboelectric charge generation.

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46

Ramlan, Nadiah, Saiful Irwan Zubairi, and Mohamad Yusof Maskat. "Response Surface Optimisation of Polydimethylsiloxane (PDMS) on Borosilicate Glass and Stainless Steel (SS316) to Increase Hydrophobicity." Molecules 27, no. 11 (May 25, 2022): 3388. http://dx.doi.org/10.3390/molecules27113388.

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Particle deposition on the surface of a drying chamber is the main drawback in the spray drying process, reducing product recovery and affecting the quality of the product. In view of this, the potential application of chemical surface modification to produce a hydrophobic surface that reduces the powder adhesion (biofouling) on the wall of the drying chamber is investigated in this study. A hydrophobic polydimethylsiloxane (PDMS) solution was used in the vertical dipping method at room temperature to determine the optimum coating parameters on borosilicate glass and stainless steel substrates, which were used to mimic the wall surface of the drying chamber, to achieve highly hydrophobic surfaces. A single-factor experiment was used to define the range of the PDMS concentration and treatment duration using the Response Surface Methodology (RSM). The Central Composite Rotatable Design (CCRD) was used to study the effects of the concentration of the PDMS solution (X1, %) and the treatment duration (X2, h) on the contact angle of the substrates (°), which reflected the hydrophobicity of the surface. A three-dimensional response surface was constructed to examine the influence of the PDMS concentration and treatment duration on contact angle readings, which serve as an indicator of the surface’s hydrophobic characteristics. Based on the optimisation study, the PDMS coating for the borosilicate glass achieved an optimum contact angle of 99.33° through the combination of a PDMS concentration of X1 = 1% (w/v) and treatment time of X2 = 4.94 h, while the PDMS coating for the stainless steel substrate achieved an optimum contact angle of 98.31° with a PDMS concentration of X1 = 1% (w/v) and treatment time of X2 = 1 h. Additionally, the infrared spectra identified several new peaks that appeared on the PDMS-treated surfaces, which represented the presence of Si-O-Si, Si-CH3, CH2, and CH3 functional groups for the substrates coated with PDMS. Furthermore, the surface morphology analysis using the Field Emission Scanning Electron Microscopy (FESEM) showed the presence of significant roughness and a uniform nanostructure on the surface of the PDMS-treated substrates, which indicates the reduction in wettability and the potential effect of unwanted biofouling on the spray drying chamber. The application of PDMS and PTFE on the optimally coated substrates successfully reduced the amount of full cream milk particles that adhered to the surface. The low surface energy of the treated surface (19–27 mJ/m2) and the slightly higher surface tension of the full cream milk (54–59 mJ/m2) resulted in a high contact angle (102–103°) and reduced the adhesion work on the treated substrates (41–46 mJ/m2) as compared to the native substrates.

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47

Poleni, Paul Emile, Nazare Pereira-Rodrigues, Denis Guimard, Yasuhiko Arakawa, Yasuyuki Sakai, and Teruo Fujii. "Surface Modification of Polydimethylsiloxane Using Low Pressure Chemical Vapour Deposition of Poly-Chloro-p-Xylene." Journal of Nano Research 20 (December 2012): 129–42. http://dx.doi.org/10.4028/www.scientific.net/jnanor.20.129.

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The capability to understand and modulate accurately the self-assembly of the extracellular matrix (ECM) components still one of the major fundamental objectives in the field of liver tissue engineering. In the present study, we put in evidence the suitability of poly-chloro-p-xylene (Parylene-C, ParC) for modulating the self-assembly of ECM (type-I collagen) microenvironment and cellular topography of human hepatocarcinoma (HepG2) and Human umbilical vascular endothelial (HUVEC) cells while coated on a polydimethylsiloxane (PDMS) substratum. Our findings demonstrated that the wettability of PDMS and ParC/PDMS were identical, while ParC/PDMS was significantly rougher than PDMS before and after collagen coating. However, the roughness and the wettability of ParC/PDMS were comparable to those of polystyrene (PS), a substratum commonly used for in vitro biological-related investigations. Type-I collagen adsorbed on ParC/PDMS and PS exhibited a dense network of microstructures around ~1 nm high and ~30-50 nm wide, whereas collagen adsorbed on PDMS had a low surface density of elongated fibrils that were ~2 nm thick and ~200 nm wide. This disparity in ECM microarchitecture leaded to distinct culture topographies of HepG2 cells (3D and 2D for PDMS and ParC/PDMS, respectively) and viability of HUVEC (2D viable HUVEC cells and non attached dead cells on ParC/PDMS and PDMS, respectively). To conclude, the observed changes in cell morphology and viability between ParC/PDMS and PDMS alone were directly related to the nature of the material which may impact the supramolecular organization of adsorbed ECM. We strongly believe that Low Pressure Chemical Vapour deposition (LPCVD) of ParC will offer promising insights into how microscale ECM modifications directly impact cell morphology and activity, leading to the development of advanced micro/nanosized tissue-engineered ParC/PDMS patterns with applications for liver tissue engineering.

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48

Lin, Yi-Ying, Yueh Chien, Jen-Hua Chuang, Chia-Ching Chang, Yi-Ping Yang, Ying-Hsiu Lai, Wen-Liang Lo, Ke-Hung Chien, Teh-Ia Huo, and Chien-Ying Wang. "Development of a Graphene Oxide-Incorporated Polydimethylsiloxane Membrane with Hexagonal Micropillars." International Journal of Molecular Sciences 19, no. 9 (August 25, 2018): 2517. http://dx.doi.org/10.3390/ijms19092517.

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Several efforts have been made on the development of bioscaffolds including the polydimethylsiloxane (PDMS) elastomer for supporting cell growth into stable sheets. However, PDMS has several disadvantages, such as intrinsic surface hydrophobicity and mechanical strength. Herein, we generated a novel PDMS-based biomimetic membrane by sequential modifications of the PMDS elastomer with graphene oxide (GO) and addition of a hexagonal micropillar structure at the bottom of the biomembrane. GO was initially homogenously mixed with pure PDMS and then was further coated onto the upper surface of the resultant PDMS. The elastic modulus and hydrophilicity were significantly improved by such modifications. In addition, the development of hexagonal micropillars with smaller diameters largely improved the ion permeability and increased the motion resistance. We further cultured retinal pigment epithelial (RPE) cells on the surface of this modified PDMS biomembrane and assayed its biocompatibility. Remarkably, the GO incorporation and coating exhibited beneficial effect on the cell growth and the new formation of tight junctions in RPE cells. Taken together, this GO-modified PDMS scaffold with polyhexagonal micropillars may be utilized as an ideal cell sheet and adaptor for cell cultivation and can be used in vivo for the transplantation of cells such as RPE cells.

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49

Joo, Haejin, Jonghyun Park, Chanutchamon Sutthiwanjampa, Hankoo Kim, Taehui Bae, Wooseob Kim, Jinhwa Choi, Mikyung Kim, Shinhyuk Kang, and Hansoo Park. "Surface Coating with Hyaluronic Acid-Gelatin-Crosslinked Hydrogel on Gelatin-Conjugated Poly(dimethylsiloxane) for Implantable Medical Device-Induced Fibrosis." Pharmaceutics 13, no. 2 (February 17, 2021): 269. http://dx.doi.org/10.3390/pharmaceutics13020269.

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Polydimethylsiloxane (PDMS) is a biocompatible polymer that has been applied in many fields. However, the surface hydrophobicity of PDMS can limit successful implementation, and this must be reduced by surface modification to improve biocompatibility. In this study, we modified the PDMS surface with a hydrogel and investigated the effect of this on hydrophilicity, bacterial adhesion, cell viability, immune response, and biocompatibility of PDMS. Hydrogels were created from hyaluronic acid and gelatin using a Schiff-base reaction. The PDMS surface and hydrogel were characterized using nuclear magnetic resonance, X-ray photoelectron spectroscopy, attenuated total reflection Fourier-transform infrared spectroscopy, and scanning electron microscopy. The hydrophilicity of the surface was confirmed via a decrease in the water contact angle. Bacterial anti-adhesion was demonstrated for Pseudomonas aeruginosa, Ralstonia pickettii, and Staphylococcus epidermidis, and viability and improved distribution of human-derived adipose stem cells were also confirmed. Decreased capsular tissue responses were observed in vivo with looser collagen distribution and reduced cytokine expression on the hydrogel-coated surface. Hydrogel coating on treated PDMS is a promising method to improve the surface hydrophilicity and biocompatibility for surface modification of biomedical applications.

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50

Cui, Heng, Qing Liu, Rui Li, Xiaoyun Wei, Yue Sun, Zixiang Wang, Lingling Zhang, Xing-Zhong Zhao, Bo Hua, and Shi-Shang Guo. "ZnO nanowire-integrated bio-microchips for specific capture and non-destructive release of circulating tumor cells." Nanoscale 12, no. 3 (2020): 1455–63. http://dx.doi.org/10.1039/c9nr07349c.

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We constructed ZnO-coated gear structure PDMS pillars microchips that simultaneously combine the advantages of a micro/nano-structure. The microchip is designed to sensitively capture and non-destructively release CTCs using ZnO nanowires.

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