Journal articles: 'Microstructured'

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Gong, Jian Liang, Bin Gang Xu, Hua Yang Yu, and Xiao Ming Tao. "Novel Honeycomb-Microstructured Asphalt Composite Coatings for Sustainable Photocatalytic Application." Advanced Materials Research 905 (April 2014): 310–13. http://dx.doi.org/10.4028/www.scientific.net/amr.905.310.

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The microstructure of asphalt materials on photocatalytic performance was studied in this work. Firstly, asphalt composite coatings with highly ordered honeycomb microstructures were fabricated by a bottom-up approach through adjusting the solution concentration and the content of polystyrene (PS) additive. Further incorporation of titanium dioxide (TiO2) nanoparticles endows the porous coatings with photocatalytic functionality. SEM images demonstrate that TiO2nanoparticles disperse and decorate on the pore walls of coating. In comparison to the compact coatings prepared by traditional method, the obtained honeycomb microstructured asphalt/PS/TiO2coatings possess an enhanced and sustainable efficiency of removing NOx. Specifically, when introducing porous microstructures to the coating, the NOxreduction efficiency is 16% higher than that of traditional compact sample and shows no attenuation in continuous use.

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Zhao, Chang Song, Jun Yong Wu, Fan Zhong Chu, Kai Rui Zhao, and Lei Yu. "Study on Preparation of Microstructured Optical Membrane." Key Engineering Materials 861 (September 2020): 159–64. http://dx.doi.org/10.4028/www.scientific.net/kem.861.159.

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Micro-structured optical film is one of the micro-optical elements and has a great market demand. This article studies the microstructured optical film formed by UV imprinting: The influence of embossing pressure on microstructure replication accuracy was explored. The larger the pressure, the better the material filling. When the pressure is 5N, the microstructure replication is complete; The relationship between the radiation intensity and warpage deformation was explored, and the decrease in the intensity of the UV light source can effectively reduce the warpage deformation; The influence of the material formula on the optical properties of the product was explored. When the oligomer content was 55%, the film had a high light transmittance. At the same time, the prepared film was subjected to an apparent inspection with good microstructure replication accuracy.Microstructured optical elements are widely used in optical fields such as semiconductors, lasers, beam shaping [1-2] and solar energy [3-5] due to their unique advantages such as small size and high performance. As a key component in many industries, it has a high market demand rate. However, the microstructure forming process is complicated, the manufacturing cost is high, and the accuracy is difficult to guarantee, which has restricted its development. With the advancement of science and technology and the increase in market demand, more and more researchers and enterprises have put their eyes on the research of preparing micro-structured optical elements.At present, the commonly used microstructures are mainly icrolens array [6-8], and the processing methods include micro-imprinting [9-10], etching [11], electron beam direct writing, and micro-injection [12], etc. This article studies the UV-curing embossing process in micro-embossing. This processing method has the advantages of fast molding, high efficiency, and environmental protection. And this process is conducive to mass production and has a broad market application prospect.In this paper, the forming process and material formulation of microstructured optical film prepared by light-cured micro-imprinting were investigated, and the microstructure morphology of the preparation was analyzed apparently.

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Sun, Jiazhen, Chenghu Yun, Bo Cui, Pingping Li, Guangping Liu, Xin Wang, and Fuqiang Chu. "A Facile Approach for Fabricating Microstructured Surface Based on Etched Template by Inkjet Printing Technology." Polymers 10, no. 11 (October 31, 2018): 1209. http://dx.doi.org/10.3390/polym10111209.

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Microstructures are playing an important role in manufacturing functional devices, due to their unique properties, such as wettability or flexibility. Recently, various microstructured surfaces have been fabricated to realize functional applications. To achieve the applications, photolithography or printing technology is utilized to produce the microstructures. However, these methods require preparing templates or masks, which are usually complex and expensive. Herein, a facile approach for fabricating microstructured surfaces was studied based on etched template by inkjet printing technology. Precured polydimethylsiloxane substrate was etched by inkjet printing water-soluble polyacrylic acid solution. Then, the polydimethylsiloxane substrate was cured and rinsed, which could be directly used as template for fabricating microstructured surfaces. Surfaces with raised dots, lines, and squares, were facilely obtained using the etched templates by inkjet printing technology. Furthermore, controllable anisotropic wettability was exhibited on the raised line microstructured surface. This work provides a flexible and scalable way to fabricate various microstructured surfaces. It would bring about excellent performance, which could find numerous applications in optoelectronic devices, biological chips, microreactors, wearable products, and related fields.

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Zhang, Dawei, Haiyang Li, Xiaoli Chen, Hongchang Qian, and Xiaogang Li. "Effect of Surface Microstructures on Hydrophobicity and Barrier Property of Anticorrosive Coatings Prepared by Soft Lithography." Advances in Materials Science and Engineering 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/342184.

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Enhancing the hydrophobicity of organic coatings retards their interaction with water and often leads to better protectiveness over metal corrosion. In this study, a soft lithography method was used to prepare epoxy coatings which showed surface microstructures in high replication to sandpapers. The effect of microstructures on coating’s hydrophobicity and barrier property was investigated. Compared to flat coatings, the microstructured coatings showed much higher water contact angles, which further increased with finer sandpapers. Determined by electrochemical impedance spectroscopy (EIS), the flat coating exhibited a higher anticorrosive performance than the microstructured coatings. With the use of finer sandpaper, the groove size of the corresponding microstructured coating was reduced. And a lower anticorrosive performance was observed since more defects might be formed in a given area of coating during the imprinting process. As the groove size of the coatings was further decreased to 5.7 µm, the microstructures became too small for water to easily penetrate through. Therefore, trapped air acted as an additional barrier and contributed to an increased anticorrosive performance compared to other microstructured coatings.

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Talmon, Yeshayahu. "Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 876–77. http://dx.doi.org/10.1017/s0424820100150216.

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To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.

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Bongarala, Manohar, Han Hu, Justin A. Weibel, and Suresh V. Garimella. "Microlayer evaporation governs heat transfer enhancement during pool boiling from microstructured surfaces." Applied Physics Letters 120, no. 22 (May 30, 2022): 221602. http://dx.doi.org/10.1063/5.0090156.

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Enhancement of the rate of boiling heat transfer, a critically significant need across a range of industrial transport processes, can be achieved by the introduction of surface microstructures. However, the precise mechanism of such enhancement is not definitively understood. We establish microlayer evaporation from the imbibed liquid layer underneath the growing vapor bubbles as the key mechanism of enhancement in boiling heat transfer coefficient for microstructured surfaces. We experimentally characterize nucleate boiling heat transfer performance on silicon surfaces custom-fabricated with controlled microstructures using HFE-7100 as the working fluid. We then undertake an analytical prediction of the microlayer evaporation from the microstructured surface. A clear dependence of the measured boiling heat transfer coefficients from microstructures of different dimensions on the predicted evaporation heat transfer coefficients allows us to conclude that microlayer evaporation governs the boiling enhancement from microstructured surfaces.

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Hu, Guohong, Fengli Huang, Chengli Tang, Jinmei Gu, Zhiheng Yu, and Yun Zhao. "High-Performance Flexible Piezoresistive Pressure Sensor Printed with 3D Microstructures." Nanomaterials 12, no. 19 (September 29, 2022): 3417. http://dx.doi.org/10.3390/nano12193417.

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Flexible pressure sensors have been widely used in health detection, robot sensing, and shape recognition. The micro-engineered design of the intermediate dielectric layer (IDL) has proven to be an effective way to optimize the performance of flexible pressure sensors. Nevertheless, the performance development of flexible pressure sensors is limited due to cost and process difficulty, prepared by inverted mold lithography. In this work, microstructured arrays printed by aerosol printing act as the IDL of the sensor. It is a facile way to prepare flexible pressure sensors with high performance, simplified processes, and reduced cost. Simultaneously, the effects of microstructure size, PDMS/MWCNTs film, microstructure height, and distance between the microstructures on the sensitivity and response time of the sensor are studied. When the microstructure size, height, and distance are 250 µm, 50 µm, and 400 µm, respectively, the sensor shows a sensitivity of 0.172 kPa−1 with a response time of 98.2 ms and a relaxation time of 111.4 ms. Studies have proven that the microstructured dielectric layer printed by aerosol printing could replace the inverted mold technology. Additionally, applications of the designed sensor are tested, such as the finger pressing test, elbow bending test, and human squatting test, which show good performance.

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Baum, Martina J., Lars Heepe, Elena Fadeeva, and Stanislav N. Gorb. "Dry friction of microstructured polymer surfaces inspired by snake skin." Beilstein Journal of Nanotechnology 5 (July 21, 2014): 1091–103. http://dx.doi.org/10.3762/bjnano.5.122.

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The microstructure investigated in this study was inspired by the anisotropic microornamentation of scales from the ventral body side of the California King Snake (Lampropeltis getula californiae). Frictional properties of snake-inspired microstructured polymer surface (SIMPS) made of epoxy resin were characterised in contact with a smooth glass ball by a microtribometer in two perpendicular directions. The SIMPS exhibited a considerable frictional anisotropy: Frictional coefficients measured along the microstructure were about 33% lower than those measured in the opposite direction. Frictional coefficients were compared to those obtained on other types of surface microstructure: (i) smooth ones, (ii) rough ones, and (iii) ones with periodic groove-like microstructures of different dimensions. The results demonstrate the existence of a common pattern of interaction between two general effects that influence friction: (1) molecular interaction depending on real contact area and (2) the mechanical interlocking of both contacting surfaces. The strongest reduction of the frictional coefficient, compared to the smooth reference surface, was observed at a medium range of surface structure dimensions suggesting a trade-off between these two effects.

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Guo, Bing, Qing Liang Zhao, Yan Hou, Cheng Ge, and Xin Yu. "Ultrasonic Vibration Assisted Grinding of Microstructures on Binderless Tungsten Carbide (WC)." Key Engineering Materials 625 (August 2014): 475–79. http://dx.doi.org/10.4028/www.scientific.net/kem.625.475.

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Microstructured optical elements made of glass are generally replicated by hot pressing with super-hard materials, such as binderless tungsten carbide (WC) and precision ceramic. However, in grinding of microstructures, problems frequently occur in terms of rough ground surface, chipping and rounding of micro-structures edges when compared to conventional grinding. In order to overcome these technological constraints, a promising precision grinding method for microstructured surfaces that applies ultrasonic vibration to improve the surface quality, and protect the edges and tips of microstructured surfaces is presented. The experimental investigation of ultrasonic vibration assisted grinding of microstructures on binderless WC is researched. The effects of ultrasonic vibration on surface roughness, form accuracy and edge radius were analyzed. The morphology of surface and array edges was examined with a scanning electron microscope (SEM), while the surface roughness was measured by a laser interferometer. And a contact probe profilometer was used to assess the form of array and radius of microstructured edges. Experimental results showed that the application of ultrasonic vibration leads to significant improvements of the surface roughness and edges of microstructures compared with traditional precision grinding processes. A micro cylinder lens array of binderless WC with surface roughness of 78nm and edge radius of less than 1μm was obtained. The novel grinding method is feasible and applicable in machining higher form accuracy microstructures.

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Lazauskas, Algirdas, Viktoras Grigaliūnas, and Dalius Jucius. "Recovery Behavior of Microstructured Thiol-Ene Shape-Memory Film." Coatings 9, no. 4 (April 20, 2019): 267. http://dx.doi.org/10.3390/coatings9040267.

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In this work, surface microstructurization was coupled with shape-memory polymer to generate reversibly tunable surface properties. A photopolymerizable thiol-ene composition comprising a mixture of pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TTT) and 2,2-dimethoxy-2-phenylacetophenone (DMPA) was used to prepare microstructured thiol-ene shape-memory film via casting and UV polymerization on the electron beam lithography fabricated arrays of 1 µm and 2 µm square pits. The mechanical deformation via compression and recovery of the surface microstructure were investigated. Results show that, after heat treatment of the deformed thiol-ene film, the recovery yields for microstructures were not worse than 90% ± 2% and 93% ± 2% for structures imprinted with 1 µm and 2 µm square pit micro imprint stamps. Additionally, heat treatment of deformed thiol-ene film resulted in the recovery of intense diffraction colors and laser diffraction patterns. This study opens up an avenue of incorporating microstructured shape-memory films for new products, e.g., optical security devices, superhydrophobic coatings, medical diagnostics and biosensors.

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Clasen, Antje, and Antonia B. Kesel. "Microstructural Surface Properties of Drifting Seeds—A Model for Non-Toxic Antifouling Solutions." Biomimetics 4, no. 2 (May 13, 2019): 37. http://dx.doi.org/10.3390/biomimetics4020037.

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A major challenge in the shipping and marine industry is the biofouling on under water surfaces. So far, biocides have been the main remedy for the prevention of the adhesion of microorganisms that is also influenced by surface topography. In recent years, research projects have explored microstructured surfaces as a non-toxic antifouling strategy. In this study, physical factors of surfaces of seeds of 43 plant species were analyzed with regards to their antifouling effects. After exposure to cold water of the North Sea during the swarming periods of the barnacles larvae, the surface microstructures of seeds without fouling of barnacles were identified and compared with each other, using a scanning electron microscope (SEM). In order to validate the findings, selected microstructured surface structure properties were transferred to technical surfaces with a 2-component silicon system and subjected to the same conditions. The results of the analyses confirmed that drifting seeds with specific microstructural surface structure properties promote biofouling defense of epibionts. These results serve as a starting point for the development of non-toxic antifouling agents based on the interaction of microstructures and geometric shapes.

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Kim, Young Ho, Jeong-Woo Sohn, Youngjae Woo, Joo-Hyun Hong, Gyu Man Kim, Bong Keun Kang, and Juyoung Park. "Preparation of Microstructure Molds of Montmorillonite/Polyethylene Glycol Diacrylate and Multi-Walled Carbon Nanotube/Polyethylene Glycol Diacrylate Nanocomposites for Miniaturized Device Applications." Journal of Nanoscience and Nanotechnology 15, no. 10 (October 1, 2015): 7860–65. http://dx.doi.org/10.1166/jnn.2015.11224.

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Environmentally friendly microstructure molds with montmorillonite (MMT) or multi-walled carbon nanotube (MWCNT) reinforced polyethylene glycol diacrylate (PEGDA) nanocomposites have been prepared for miniaturized device applications. The micropatterning of MMT/PEGDA and MWCNT/PEGDA with 0.5 to 2.0 wt% of MMTs and MWCNTs was achieved through a UV curing process with micro-patterned masks. Hexagonal dot arrays and complex patterns for microstructures of the nanocomposites were produced and characterized with an optical microscope; their thermal properties were studied by thermogravimetric analysis (TGA). The TGA results showed that these nanocomposites were thermally stable up to 350 °C. Polydimethylsiloxane thin replicas with different microstructures were prepared by a casting method using the microstructured nanocomposites as molds. It is considered that these microstructure molds of the nanocomposites can be used as microchip molds to fabricate nanobio-chips and medical diagnostic chip devices.

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Argyros, Alexander. "Microstructures in Polymer Fibres for Optical Fibres, THz Waveguides, and Fibre-Based Metamaterials." ISRN Optics 2013 (February 12, 2013): 1–22. http://dx.doi.org/10.1155/2013/785162.

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This paper reviews the topic of microstructured polymer fibres in the fields in which these have been utilised: microstructured optical fibres, terahertz waveguides, and fibre-drawn metamaterials. Microstructured polymer optical fibres were initially investigated in the context of photonic crystal fibre research, and several unique features arising from the combination of polymer and microstructure were identified. This lead to investigations in sensing, particularly strain sensing based on gratings, and short-distance data transmission. The same principles have been extended to waveguides at longer wavelengths, for terahertz frequencies, where microstructured polymer waveguides offer the possibility for low-loss flexible waveguides for this frequency region. Furthermore, the combination of microstructured polymer fibres and metals is being investigated in the fabrication of metamaterials, as a scalable method for their manufacture. This paper will review the materials and fabrication methods developed, past and current research in these three areas, and future directions of this fabrication platform.

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Yang, Chun Hui, Ilchat Sabirov, Jonathan Mullins, and Peter D. Hodgson. "Analytic Prediction of Structural Stress-Strain Relations of Microstructured Metal." Advanced Materials Research 32 (February 2008): 83–86. http://dx.doi.org/10.4028/www.scientific.net/amr.32.83.

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Nanostructured and ultra-fine grained metals have higher strength but extremely limited ductility compared to coarse grained metals. However, their ductility can be greatly improved by introducing a specific range of grain sizes in the microstructures. In the paper, multiscale unit cell approach (UCA) is developed and applied to predict the averaged stress-strain relations of the multiscale microstructure metals. The unit cell models are three-phase structured at different scale lengths of 100 nm, 1 μm and 10 μm with different volume fractions and periodic boundary conditions. The contributions of multi-scale microstructures to the macroscopic structural properties of metals are also studied using a analytic approach—two-step mean-field method (TSMF), where three microstructural parameters are introduced and thus mechanical properties such as strength and ductility are presented as a function of these parameters. For verification of these proposed numerical and theoretical algorithms, the structural properties of the pure nickel with three-grain microstructures are studied and the results from FEA and the proposed theory have good agreement.

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Lombardo, Mariateresa, and Harm Askes. "Elastic wave dispersion in microstructured membranes." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 466, no. 2118 (January 13, 2010): 1789–807. http://dx.doi.org/10.1098/rspa.2009.0516.

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The effect of microstructural properties on the wave dispersion in linear elastic membranes is addressed in this paper. A periodic spring-mass lattice at the lower level of observation is continualized and a gradient-enriched membrane model is obtained to account for the characteristic microstructural length scale of the material. In the first part of this study, analytical investigations show that the proposed model is able to correctly capture the physical phenomena of wave dispersion in microstructured membrane which is overlooked by classical continuum theories. In the second part, a finite-element discretization of microstructured membrane is formulated by introducing the pertinent inertia and stiffness terms. Importantly, the proposed modifications do not increase the size of the problem compared wiith classical elasticity. Numerical simulations confirm that the vibrational properties are affected by the microstructural characteristics of the material, particularly in the high-frequency regime.

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Orellana, Nicole, Elizabeth Sánchez, Diego Benavente, Pablo Prieto, Javier Enrione, and Cristian A. Acevedo. "A New Edible Film to Produce In Vitro Meat." Foods 9, no. 2 (February 13, 2020): 185. http://dx.doi.org/10.3390/foods9020185.

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In vitro meat is a novel concept of food science and biotechnology. Methods to produce in vitro meat employ muscle cells cultivated on a scaffold in a serum-free medium using a bioreactor. The microstructure of the scaffold is a key factor, because muscle cells must be oriented to generate parallel alignments of fibers. This work aimed to develop a new scaffold (microstructured film) to grow muscle fibers. The microstructured edible films were made using micromolding technology. A micromold was tailor-made using a laser cutting machine to obtain parallel fibers with a diameter in the range of 70–90 µm. Edible films were made by means of solvent casting using non-mammalian biopolymers. Myoblasts were cultured on flat and microstructured films at three cell densities. Cells on the microstructured films grew with a muscle fiber morphology, but in the case of using the flat film, they only produced unorganized cell proliferation. Myogenic markers were assessed using quantitative polymerase chain reaction. After 14 days, the expression of desmin, myogenin, and myosin heavy chain were significantly higher in microstructured films compared to the flat films. The formation of fiber morphology and the high expression of myogenic markers indicated that a microstructured edible film can be used for the production of in vitro meat.

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Cai, Yukui, Wenlong Chang, Xichun Luo, and Yi Qin. "Superhydrophobicity of microstructured surfaces on zirconia by nanosecond pulsed laser." Journal of Micromanufacturing 2, no. 1 (October 9, 2018): 5–14. http://dx.doi.org/10.1177/2516598418799933.

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This article presents a systematic approach to improve the hydrophobicity of microstructured surfaces. It includes a contact angle prediction model for microstructures obtained by nanosecond pulsed laser. Combining with the theoretical constraints for stable Cassie–Baxter state, this approach can be used to optimize microstructures dimensions for maximizing surface hydrophobicity. Laser machining experiments were conducted to evaluate the prediction model. It shows that the proposed systematic approach can accurately predict the contact angle and obtain microstructures dimensions for maximizing surface hydrophobicity. The results also indicate that the contact angle increases with the decrease of pitch of the microstructures. Superhydrophobicity with maximum contact angle of 155.7° is obtained, for the first time, on a microstructured surface (P030) of zirconia with a pitch of 30 µm machined under a laser power at 8W.

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Hopmann, Christian, and Florian Petzinka. "Use of variothermal heating for the extrusion embossing of microstructured poly(methylmethacrylate) and polycarbonate optical films." Journal of Plastic Film & Sheeting 34, no. 1 (March 20, 2017): 98–112. http://dx.doi.org/10.1177/8756087917699245.

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The importance of microstructured parts and extrudates is rising because of the increasing functional integration in many different fields of application, for example in the automotive industry and medical technology. Variothermal extrusion embossing is a continuous process that combines plastic film production with the application of large-area microstructures. The process utilizes an embossing roll and an external heating device to continuously imprint the desired structure into film during extrusion. Through this microstructuring, it is possible to integrate innovative functions into a film. Present efforts are focused on forming optical structures (micro-optics) on polycarbonate and poly(methylmethacrylate) films. This article deals with process control requirements that are necessary to successfully apply this technology, and also demonstrate how, through suitable process parameter selection, high-quality microstructures can be effectively embossed on the films. Different microstructures between 24 and 165 µm in height and between 100 and 200 µm in width are tested. With poly(methylmethacrylate) better microstructure reproduction could be achieved than with polycarbonate.

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Wang, Zhaochang, Jiawei Ji, Yuhang Guo, Tongtong Tao, Xidong Hu, Yongqing Zhu, Xiaojun Liu, Kun Liu, and Yunlong Jiao. "Robust air cavity generation on sacrificial microstructures for sustainable underwater drag reduction." Applied Physics Letters 121, no. 18 (October 31, 2022): 181602. http://dx.doi.org/10.1063/5.0128049.

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Reducing fluid frictional drag at the solid–liquid interface is a promising strategy for improving the hydrodynamic properties of the structure in water, though so far it has remained unattainable without robust air cavities. Herein, we report a durable generation strategy of robust air cavity on the rough microstructured surface, which could achieve stable drag reduction even after 2000th water entry test. It is worth noting that the generation strategy is almost independent of the wear of surface microstructure, as the worn microstructures still keep a rough morphology and would alter the capillary driving force and prevent the spreading of the liquid film along the structure body. Therefore, the triple contact line is pinned at the solid–liquid interface and induces the generation of a complete air cavity. Comprehensive evaluation, including the mechanical and chemical stability tests, confirm that the microstructured spheres could produce robust cavities even after harsh destruction, and they also reduce the hydrodynamic drag by more than 70.8% at a higher Reynolds number of ∼4.9 × 104. Finally, the boundary slip at the solid–liquid interface of the microstructured surface is simulated, which concludes that the decrease in the contact angle at air–liquid interface and fraction of solid–liquid contact area on the wall would enhance the slip length of fluid, thus resulting in an obvious decreasing of frictional resistance at the solid–liquid interface. We believe that the present work provides a perspective on the sustainable construction of the robust cavity which may have important potential application value in the field of drag reduction.

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Demirörs, Ahmet Faik, Diana Courty, Rafael Libanori, and André R. Studart. "Periodically microstructured composite films made by electric- and magnetic-directed colloidal assembly." Proceedings of the National Academy of Sciences 113, no. 17 (April 11, 2016): 4623–28. http://dx.doi.org/10.1073/pnas.1524736113.

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Living organisms often combine soft and hard anisotropic building blocks to fabricate composite materials with complex microstructures and outstanding mechanical properties. An optimum design and assembly of the anisotropic components reinforces the material in specific directions and sites to best accommodate multidirectional external loads. Here, we fabricate composite films with periodic modulation of the soft–hard microstructure by simultaneously using electric and magnetic fields. We exploit forefront directed-assembly approaches to realize highly demanded material microstructural designs and showcase a unique example of how one can bridge colloidal sciences and composite technology to fabricate next-generation advanced structural materials. In the proof-of-concept experiments, electric fields are used to dictate the position of the anisotropic particles through dielectrophoresis, whereas a rotating magnetic field is used to control the orientation of the particles. By using such unprecedented control over the colloidal assembly process, we managed to fabricate ordered composite microstructures with up to 2.3-fold enhancement in wear resistance and unusual site-specific hardness that can be locally modulated by a factor of up to 2.5.

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Colatosti, Marco, Farui Shi, Nicholas Fantuzzi, and Patrizia Trovalusci. "Dynamic Characterization of Hexagonal Microstructured Materials with Voids from Discrete and Continuum Models." Materials 15, no. 21 (October 27, 2022): 7524. http://dx.doi.org/10.3390/ma15217524.

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The mechanical response of materials such as fiber and particle composites, rocks, concrete, and granular materials, can be profoundly influenced by the existence of voids. The aim of the present work is to study the dynamic behavior of hexagonal microstructured composites with voids by using a discrete model and homogenizing materials, such as micropolar and classical Cauchy continua. Three kinds of hexagonal microstructures, named regular, hourglass, and skew, are considered with different length scales. The analysis of free vibration of a panel described as a discrete system, as a classical and as a micropolar continuum, and the comparison of results in terms of natural frequencies and modes show the advantage of the micropolar continuum in describing dynamic characteristics of orthotropic composites (i.e., regular and hourglass microstructures) with respect to the Cauchy continuum, which gives a higher error in frequency evaluations for all three hexagonal microstructured materials. Moreover, the micropolar model also satisfactorily predicts the behavior of skewed microstructured composites. Another advantage shown here by the micropolar continuum is that, like the discrete model, this continuum is able to present the scale effect of microstructures, while maintaining all the advantages of the field description. The effect of void size is also investigated and the results show that the first six frequencies of the current problem decrease by increasing in void size.

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Schrader, Tobias, Martin Weschta, Marion Merklein, Stephan Tremmel, Ulf Engel, and Sandro Wartzack. "Tribological Aspects in Manufacturing Processes of Microstructured Components and their Tribological Behavior in Operation." Advanced Materials Research 966-967 (June 2014): 323–35. http://dx.doi.org/10.4028/www.scientific.net/amr.966-967.323.

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An ever increasing mobility and a shortage of resources lead to restrictive politically driven limits for fuel consumption as well as an increasing demand of customers for efficient vehicles. Though electrification of cars proceeds, combustion engines will play an important role for conventional and hybrid concepts within next decades. Thus, for a contribution to increasing energy efficiency of vehicles it is vital to trace sources of friction losses and to identify possibilities for friction reduction in combustion engines. Therefore, the follower as a main contributor to friction losses in valve trains was chosen as a demonstrator for friction reduction effects by microstructured components. However, the realization of theoretically advantageous microstructures with filigree geometries is challenging for manufacturing technologies. The present study focuses on the elaboration of a technological basis for a repeatable production of components with microstructured surfaces by a combined cup backward extrusion micro coining process, coping with the demands of large-lot production. For realization of a high accuracy the influence of friction on geometry of microstructured components was investigated. In addition, running-in of components is decisive for final geometry and tribological behavior of microstructured surfaces and hence considered as well.

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Xue, Bin, Haiyi Xie, Jinxu Zhao, Jianming Zheng, and Chunye Xu. "Flexible Piezoresistive Pressure Sensor Based on Electrospun Rough Polyurethane Nanofibers Film for Human Motion Monitoring." Nanomaterials 12, no. 4 (February 21, 2022): 723. http://dx.doi.org/10.3390/nano12040723.

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Flexible piezoresistive pressure sensors have been attracted a lot of attention due to their simple mechanism, easy fabrication, and convenient signal acquisition and analysis. Herein, a new flexible piezoresistive sensor based on microstructured electrospun rough polyurethane (PU) nanofibers film is assembled. The microstructured PU film with tiny bumps is prepared in one step via electrospinning technology, which imparts a microstructured rough upper surface and a smooth lower surface. With this unique microstructure, we have made it possible for PU/Ag films to serve as sensing layers for piezoresistive sensors by introducing a silver conductive layer on the surface of electrospun PU film. The fabricated piezoresistive pressure sensor delivers high sensitivity (10.53 kPa−1 in the range of 0–5 kPa and 0.97 kPa−1 in the range of 6–15 kPa), fast response time (60 ms), fast recovery time (30 ms), and long-time stability (over 10,000 cycles). This study presents a fabrication strategy to prepare the microstructured PU nanofiber film using electrospinning technology directly, and the as-developed sensor shows promise in applications such as wrist pulse measurement, finger movement monitoring, etc., proving its great potential for monitoring human activities.

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Nagata, I., A. Kawana, and N. Nakatsuji. "Perpendicular contact guidance of CNS neuroblasts on artificial microstructures." Development 117, no. 1 (January 1, 1993): 401–8. http://dx.doi.org/10.1242/dev.117.1.401.

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Rodent CNS neuroblasts show parallel and perpendicular contact guidance behaviors on aligned neurite bundles in microexplant cultures (Nakatsuji, N. and Nagata, I. (1989) Development, 106, 441–447; N. I. and N. N. (1991) ibid., 112, 581–590). To test the hypothesis that the physical surface structure of the neurite bundle causes the perpendicular contact guidance, we cultured dissociated neuroblasts on quartz plates on which grating-like microstructures were fabricated by lithographic techniques. Various types of CNS neuroblasts, but not PNS neurons, oriented their processes and migrated both perpendicular and parallel to the axis of the microstructure. Perpendicular orientation was frequently observed when the microstructured grooves had depths between 0.3 micron and 0.8 micron and a width of 1 micron, which roughly mimics a tightly aligned neurite bundle. Thus, CNS neuroblasts have the ability to extend their processes and migrate perpendicular to aligned surface microstructures.

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Shi, Farui, Nicholas Fantuzzi, Patrizia Trovalusci, Yong Li, and Zuoan Wei. "Stress Field Evaluation in Orthotropic Microstructured Composites with Holes as Cosserat Continuum." Materials 15, no. 18 (September 6, 2022): 6196. http://dx.doi.org/10.3390/ma15186196.

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It is known that the presence of microstructures in solids such as joints and interfaces has an essential influence on the studies of the development of advanced materials, rock mechanics, civil engineering, and so on. However, microstructures are often neglected in the classical local (Cauchy) continuum model, resulting in inaccurate descriptions of the behavior of microstructured materials. In this work, in order to show the impact of microstructures, an implicit ‘non-local’ model, i.e., micropolar continuum (Cosserat), is used to numerically investigate the effects of direction and scale of microstructures on the tension problem of a composite plate with a circular hole. The results show that distributions of field variables (such as displacements and stresses) have an obvious directionality with respect to the microstructures’ direction. As the scale of microstructures increases, such a direction effect becomes more evident. Unlike the isotropic material where stress concentration occurs at the vertex of the hole and the stress concentration factor is close to 3, for the microstructured composite, the stress concentration can be observed at any location depending on the microstructures’ directions, and the concentration factor can exceed 3 to a maximum close to 9 as the increasing scale of microstructures. In addition, differences in the mechanical behavior between Cosserat and Cauchy models can be also observed; such differences are more evident for the material showing a pronounced orthotropic nature.

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Sharma, Sanchit, Diego Laramore, Taylor Ochs, Douglas S. McGregor, Steven L. Bellinger, Walter J. McNeil, and Amir A. Bahadori. "Preliminary benchmarks and analysis of boundary conditions in a trenched microstructured silicon radiation detector." Journal of Applied Physics 131, no. 13 (April 7, 2022): 134503. http://dx.doi.org/10.1063/5.0087397.

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Microstructured neutron detectors have the benefit of enhanced neutron detection efficiency as compared to planar devices, achieved by etching 6LiF-filled trenches on the top surface of a silicon PIN diode. This sensor geometry results in a complex electric field distribution and depletion characteristics within the diode under reverse bias. For the first time on record, the effects of a fixed oxide charge on the microstructured device depletion characteristics and mobile carrier transport is investigated. Prototype detectors were fabricated with non-conformal surface doping. Capacitance voltage and current voltage measurements were performed for these prototypes and compared with COMSOL Multiphysics simulations. A spectral response from an 241Am alpha particle source was acquired and analyzed. It was found that monoenergetic alpha particles produce three prominent peaks in the pulse height spectrum output by the device. The peaks were confirmed by simulations to correlate with dead layers and incident trajectories into the microstructure. It was also found that significant differences in pulse rise time result, corresponding with events arriving in a low-field region in the fins and a high-field region in the bulk. Geant4 was utilized for radiation transport, interaction modeling, and benchmarking the spectral data. The results of this simulation work provide confidence in the ability to attain and benchmark electrical characteristics and spectral data for semiconductor radiation detectors employing complex microstructures.

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Cano, Irene G., S. Dosta, R. Caldeira, J. R. Miguel, and J. M. Guilemany. "Production and Characterisation of Metastable Al₂O₃-TiO₂ Coatings Obtained by APS + Quench." Materials Science Forum 587-588 (June 2008): 153–56. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.153.

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It is well known that microstructure evolution during rapid solidification depends on the rate between undercooling and solidification velocity. Microstructural evolution in a nonequilibrium solidification process depends critically on the melt undercooling and growth (solidification) velocities of competing phases. One way of obtaining metastable structures is by Thermal Spray Technology. Metastable coatings can be produced starting from microstructured powders through Atmospheric Plasma Spray (APS) technique, followed by a quenching route. The initial powders are melted during the spraying and deposited over a substrate that is quenched with nitrogen feeders, producing metastable coatings. The obtained coatings were characterized using XRD, SEM, FESEM and TEM in the Thermal Spray Centre (CPT) of the University of Barcelona. The properties of such coatings were studied by hardness, obtaining promising results.

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Dikici, Tuncay, and Mustafa Toparli. "Microstructure and mechanical properties of nanostructured and microstructured TiO2 films." Materials Science and Engineering: A 661 (April 2016): 19–24. http://dx.doi.org/10.1016/j.msea.2016.03.023.

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29

Baum, Martina J., Lars Heepe, and Stanislav N. Gorb. "Friction behavior of a microstructured polymer surface inspired by snake skin." Beilstein Journal of Nanotechnology 5 (January 24, 2014): 83–97. http://dx.doi.org/10.3762/bjnano.5.8.

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The aim of this study was to understand the influence of microstructures found on ventral scales of the biological model, Lampropeltis getula californiae, the California King Snake, on the friction behavior. For this purpose, we compared snake-inspired anisotropic microstructured surfaces to other microstructured surfaces with isotropic and anisotropic geometry. To exclude that the friction measurements were influenced by physico-chemical variations, all friction measurements were performed on the same epoxy polymer. For frictional measurements a microtribometer was used. Original data were processed by fast Fourier transformation (FFT) with a zero frequency related to the average friction and other peaks resulting from periodic stick-slip behavior. The data showed that the specific ventral surface ornamentation of snakes does not only reduce the frictional coefficient and generate anisotropic frictional properties, but also reduces stick-slip vibrations during sliding, which might be an adaptation to reduce wear. Based on this extensive comparative study of different microstructured polymer samples, it was experimentally demonstrated that the friction-induced stick-slip behavior does not solely depend on the frictional coefficient of the contact pair.

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30

Kulikouskaya, V. I., V. V. Nikalaichuk, A. P. Bonartsev, I. G. Chyshankou, E. A. Akoulina, I. V. Demianova, G. A. Bonartseva, К. S. Hileuskaya, and V. V. Voinova. "Fabrication of microstructured poly(3-hydroxybutyrate) films with controlled surface topography." Proceedings of the National Academy of Sciences of Belarus, Chemical Series 58, no. 2 (June 8, 2022): 135–48. http://dx.doi.org/10.29235/1561-8331-2022-58-2-135-148.

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The possibility of fabrication of microstructured poly-3-hydroxybutyrate films by self-assembly water microdroplets technique, using artificial templates and polymer inverse emulsions has been studied. It has been established that self-assembly water microdroplets technique allows forming ordered microstructures of poly-3-hydroxybutyrate with a hexagonal arrangement of cells with an adjustable diameter from 1 to 4 цт. It has been shown that application of inverse emulsions of poly-3-hydroxybutyrate allows us to fabricate porous films with a pore size in the range from 0.4 to 3 ^m, while the structure of the films and the pore size can be controlled by changing the polymer concentration in the dispersion medium and the volume ratio of the phases. Using spin-coating technique and artificial templates, it is possible to obtain poly-3-hydroxybutyrate microstructured replicas, which are characterized by a high degree of uniformity and the absence of defective areas. It has been shown that the formed microstructured poly-3-hydroxybutyrate films with controlled surface topography are promising for use as scaffolds for stem cells.

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31

Huang, Zhihong, James E. Carey, Mingguo Liu, Xiangyi Guo, Eric Mazur, and Joe C. Campbell. "Microstructured silicon photodetector." Applied Physics Letters 89, no. 3 (July 17, 2006): 033506. http://dx.doi.org/10.1063/1.2227629.

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32

Kerbage, Charles, and Benjamin J. Eggleton. "Microstructured Optical Fibers." Optics and Photonics News 13, no. 9 (September 1, 2002): 38. http://dx.doi.org/10.1364/opn.13.9.000038.

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33

Chaize, Barnabé, Michel Nguyen, Tristan Ruysschaert, Véronique le Berre, Emmanuelle Trévisiol, Anne-Marie Caminade, Jean Pierre Majoral, et al. "Microstructured Liposome Array." Bioconjugate Chemistry 17, no. 1 (January 2006): 245–47. http://dx.doi.org/10.1021/bc050273p.

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34

Dunsch, L., P. Rapta, A. Neudeck, A. Bartl, R. M. Peters, D. Reinecke, and I. Apfelstedt. "Microstructured conducting polymers." Synthetic Metals 85, no. 1-3 (March 1997): 1401–2. http://dx.doi.org/10.1016/s0379-6779(97)80292-5.

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35

Renken, Albert. "Microstructured Reactor Systems." CHIMIA International Journal for Chemistry 56, no. 11 (November 1, 2002): 597. http://dx.doi.org/10.2533/000942902777680027.

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36

Andrews, Steven R. "Microstructured terahertz waveguides." Journal of Physics D: Applied Physics 47, no. 37 (August 28, 2014): 374004. http://dx.doi.org/10.1088/0022-3727/47/37/374004.

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37

Büttgenbach, S., N. Lucas, and P. Sichler. "Microstructured Plasma Sources." Contributions to Plasma Physics 49, no. 9 (November 2009): 624–30. http://dx.doi.org/10.1002/ctpp.200910066.

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38

Valizadeh, Iman, and Oliver Weeger. "Nonlinear multiscale simulation of instabilities due to growth of an elastic film on a microstructured substrate." Archive of Applied Mechanics 90, no. 11 (July 12, 2020): 2397–412. http://dx.doi.org/10.1007/s00419-020-01728-w.

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Abstract The objective of this contribution is the numerical investigation of growth-induced instabilities of an elastic film on a microstructured soft substrate. A nonlinear multiscale simulation framework is developed based on the FE2 method, and numerical results are compared against simplified analytical approaches, which are also derived. Living tissues like brain, skin, and airways are often bilayered structures, consisting of a growing film on a substrate. Their modeling is of particular interest in understanding biological phenomena such as brain development and dysfunction. While in similar studies the substrate is assumed as a homogeneous material, this contribution considers the heterogeneity of the substrate and studies the effect of microstructure on the instabilities of a growing film. The computational approach is based on the mechanical modeling of finite deformation growth using a multiplicative decomposition of the deformation gradient into elastic and growth parts. Within the nonlinear, concurrent multiscale finite element framework, on the macroscale a nonlinear eigenvalue analysis is utilized to capture the occurrence of instabilities and corresponding folding patterns. The microstructure of the substrate is considered within the large deformation regime, and various unit cell topologies and parameters are studied to investigate the influence of the microstructure of the substrate on the macroscopic instabilities. Furthermore, an analytical approach is developed based on Airy’s stress function and Hashin–Shtrikman bounds. The wavelengths and critical growth factors from the analytical solution are compared with numerical results. In addition, the folding patterns are examined for two-phase microstructures and the influence of the parameters of the unit cell on the folding pattern is studied.

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Suresh, Srinivasan A., Capella F. Kerst, Mark R. Cutkosky, and Elliot W. Hawkes. "Spatially variant microstructured adhesive with one-way friction." Journal of The Royal Society Interface 16, no. 150 (January 2019): 20180705. http://dx.doi.org/10.1098/rsif.2018.0705.

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Surface microstructures in nature enable diverse and intriguing properties, from the iridescence of butterfly wings to the hydrophobicity of lotus leaves to the controllable adhesion of gecko toes. Many artificial analogues exist; however, there is a key characteristic of the natural materials that is largely absent from the synthetic versions—spatial variation. Here we show that exploiting spatial variation in the design of one class of synthetic microstructure, gecko-inspired adhesives, enables one-way friction, an intriguing property of natural gecko adhesive. When loaded along a surface in the preferred direction, our adhesive material supports forces 100 times larger than when loaded in the reverse direction, representing an asymmetry significantly larger than demonstrated in spatially uniform adhesives. Our study suggests that spatial variation has the potential to advance artificial microstructures, helping to close the gap between synthetic and natural materials.

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40

Biessikirski, Andrzej, Suzana Gotovac Atlagić, Mateusz Pytlik, Łukasz Kuterasiński, Michał Dworzak, Michał Twardosz, Dagmara Nowak-Senderowska, and Bogna Daria Napruszewska. "The Influence of Microstructured Charcoal Additive on ANFO’s Properties." Energies 14, no. 14 (July 19, 2021): 4354. http://dx.doi.org/10.3390/en14144354.

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The verification of the blasting parameters of Ammonium Nitrate Fuel Oil (ANFO) with the addition of microstructured charcoal (MC) produced by destructive wood distillation was performed. Additional investigation of specific surface and pore distribution by the nitrogen adsorption of the two granulations of MC was also carried out. High-resolution scanning electron microscopy was used for morphology evaluation and revealed smoothening of the initially developed external surface of carbon with intensive milling. In addition, the analysis of the thermal properties of the studied samples (TG/DSC) indicated that the size of the microstructured charcoal additives influenced the decomposition temperature of the prepared materials. The explosives containing microstructured charcoal grains of −90 μm underwent decomposition at lower temperatures in comparison with those containing higher sizes of microstructure charcoal grains (−1.18 mm), for which the decomposition temperature reached 292 °C. The obtained results of blasting parameters compared to the results derived from thermodynamic simulation showed the non-ideal character of the explosives (much lower values of blasting parameters than in established thermodynamic models). It was indicated that higher velocities of detonations (VOD) were obtained for non-ideal explosives where finer MC grains were added. Blasting tests confirmed that the studied type of MC can be applied as an additive to the ANFO.

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41

Liu, De Wei, Yong Guang Huang, Xiao Ning Zhu, Xi Yuan Wang, Hai Juan Yu, Xue Chun Lin, Ming Hua Chen, and Hong Liang Zhu. "Surface Morphology and Infrared Absorption of Silicon Irradiated by Picosecond Laser Pulses in SF₆." Advanced Materials Research 418-420 (December 2011): 77–81. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.77.

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The microstructured samples were prepared by irradiating silicon surface with picosecond laser pulses in SF6. The surface morphology of microstructured samples irradiated at different laser fluence was characterized by SEM. The samples exhibited high optical absorptance over a wide wavelength range between 300 and 2700 nm. The absorptance of samples irradiated with the fluence of 1.0 J/cm2was measured to be up to 95% between 1100 and 2700 nm. The infared absorptance of the surface-structured samples increased with increasing fluence. Whereas, as the annealing temperature was increased, the infared absorptance of the samples irradiated at the same fluence decreased. A tentative explanation for the effects of laser fluence and annealing temperature on the infared absorptance has been proposed based on the formation of mid-band gap impurity bands and the multiple reflections of light between microstructures.

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42

Pfleging, W., T. Hanemann, M. Torge, and W. Bernauer. "Rapid fabrication and replication of metal, ceramic and plastic mould inserts for application in microsystem technologies." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 217, no. 1 (January 1, 2003): 53–63. http://dx.doi.org/10.1243/095440603762554613.

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The process strategy for the rapid fabrication of microcomponents made of polymers will be presented. Different fabrication routes have been developed at Forschungszentrum Karlsruhe GmbH within the microsystem technology programme focusig on replication techniques. Single prototypes can be generated by the direct patterning of plastics with excimer laser radiation. For the fabrication of very small series laser-assisted micromachining, neodymium-doped yttrium aluminium garnet (Nd:YAG) and krypton fluorine (KrF) excimer laser radiation allows for the rapid manufacturing of microstructured mould inserts made of plastics, steel, cemented carbide or ceramics. The applied mould insert material depends on the achievable low surface roughness values essential for the subsequent moulding process. Plastic replication such as hot embossing, injection moulding or reaction injection moulding of the generated microstructured mould inserts gives access to mouldings carrying structural details in the micrometre range and/or high aspect ratio microstructures.

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43

Walker, S., E. Naranjo, S. Chiruvolu, and J. Zasadzinski. "TEM investigations of self-assembly through physical synthesis." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 436–37. http://dx.doi.org/10.1017/s0424820100169912.

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A novel way of enlarging the realm of surfactant solution microstructure is the "physical synthesis" of new microstructures and surfactant-templated materials by mixing simple surfactants or surfactant and inorganic and ionic species. Mixing can often produce properties not possessed by any one species alone. As we have recently shown, mixtures of single-tailed cationic and anionic surfactants associate in solution to form a quasi-double-tailed catanionic surfactant that forms bilayers rather than the simple micelles each species would form on its own. Mixed surfactant systems apparently produce new microstructures by altering the intermolecular and interaggregate forces in ways impossible for single component systems. In addition to spontaneous vesicles, we have found other new microstructures including dilute lamellar and L3 phases depending on the details of the surfactant mixture. Surfactant interactions with ionic species also play an important role in the in synthesis of a new M41S family of mesoporous silicas, and are likely to be important in the templating of biominerals at interfaces. By understanding the molecular and chemical basis of these interactions, we can begin to tailor new microstructured and/or biomimetic materials by controlling surfactant aggregation and phase behavior through physical synthesis rather than through much more elaborate chemical synthesis.

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Chou, Ding-Chin, Shang-Hui Yang, Jian-Shian Lin, Fuh-Shyang Juang, and Yoshimi Takeuchi. "Using Ultraprecision Machining to Fabricate LED Packaging Exhibiting High Luminous Intensity." International Journal of Automation Technology 13, no. 3 (May 5, 2019): 397–406. http://dx.doi.org/10.20965/ijat.2019.p0397.

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In this study, a phosphor was coated on a microstructured film to achieve light control. This process resulted in a large-area phosphor film and enabled the microstructure to be packaged directly into the LED body. Thus, the LEDs retain their air and water barrier functions, control light, achieve higher forward luminous intensity, and have a wider scope of applications. Roll-to-roll processing was performed to mold a microstructure and phosphor on polyethylene terephthalate (PET) film by applying ultraviolet light. This approach expedited the preparation of a large-area phosphor film and enabled the precise control of the thickness and evenness of the phosphor layer, thus ensuring uniform light distribution and eliminating the yellow halo within the light body induced by the uneven thickness of the phosphor layer. The experimental results revealed that the luminous intensity of the LED to which the microstructured PET film was attached at 0° (center) increased by 11.88% relative to the luminous intensity of the LED without the film. Moreover, at 30° to −30°, the luminous intensity of the LED with the film improved by 10.36%. Therefore, the device retained its color uniformity and achieved higher forward luminous intensity.

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Zhou, Xi, Yongna Zhang, Jun Yang, Jialu Li, Shi Luo, and Dapeng Wei. "Flexible and Highly Sensitive Pressure Sensors Based on Microstructured Carbon Nanowalls Electrodes." Nanomaterials 9, no. 4 (April 1, 2019): 496. http://dx.doi.org/10.3390/nano9040496.

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Wearable pressure sensors have attracted widespread attention in recent years because of their great potential in human healthcare applications such as physiological signals monitoring. A desirable pressure sensor should possess the advantages of high sensitivity, a simple manufacturing process, and good stability. Here, we present a highly sensitive, simply fabricated wearable resistive pressure sensor based on three-dimensional microstructured carbon nanowalls (CNWs) embedded in a polydimethylsiloxane (PDMS) substrate. The method of using unpolished silicon wafers as templates provides an easy approach to fabricate the irregular microstructure of CNWs/PDMS electrodes, which plays a significant role in increasing the sensitivity and stability of resistive pressure sensors. The sensitivity of the CNWs/PDMS pressure sensor with irregular microstructures is as high as 6.64 kPa−1 in the low-pressure regime, and remains fairly high (0.15 kPa−1) in the high-pressure regime (~10 kPa). Both the relatively short response time of ~30 ms and good reproducibility over 1000 cycles of pressure loading and unloading tests illustrate the high performance of the proposed device. Our pressure sensor exhibits a superior minimal limit of detection of 0.6 Pa, which shows promising potential in detecting human physiological signals such as heart rate. Moreover, it can be turned into an 8 × 8 pixels array to map spatial pressure distribution and realize array sensing imaging.

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Park, Jonghwa, Marie Kim, Youngoh Lee, Heon Sang Lee, and Hyunhyub Ko. "Fingertip skin–inspired microstructured ferroelectric skins discriminate static/dynamic pressure and temperature stimuli." Science Advances 1, no. 9 (October 2015): e1500661. http://dx.doi.org/10.1126/sciadv.1500661.

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In human fingertips, the fingerprint patterns and interlocked epidermal-dermal microridges play a critical role in amplifying and transferring tactile signals to various mechanoreceptors, enabling spatiotemporal perception of various static and dynamic tactile signals. Inspired by the structure and functions of the human fingertip, we fabricated fingerprint-like patterns and interlocked microstructures in ferroelectric films, which can enhance the piezoelectric, pyroelectric, and piezoresistive sensing of static and dynamic mechanothermal signals. Our flexible and microstructured ferroelectric skins can detect and discriminate between multiple spatiotemporal tactile stimuli including static and dynamic pressure, vibration, and temperature with high sensitivities. As proof-of-concept demonstration, the sensors have been used for the simultaneous monitoring of pulse pressure and temperature of artery vessels, precise detection of acoustic sounds, and discrimination of various surface textures. Our microstructured ferroelectric skins may find applications in robotic skins, wearable sensors, and medical diagnostic devices.

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Tse, Ming-Leung, Zhengyong Liu, Lok-Hin Cho, Chao Lu, Ping-Kong Wai, and Hwa-Yaw Tam. "Superlattice Microstructured Optical Fiber." Materials 7, no. 6 (June 16, 2014): 4567–73. http://dx.doi.org/10.3390/ma7064567.

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Oermann, Michael R., Heike Ebendorff-Heidepriem, David J. Ottaway, David G. Lancaster, Peter J. Veitch, and Tanya M. Monro. "Extruded Microstructured Fiber Lasers." IEEE Photonics Technology Letters 24, no. 7 (April 2012): 578–80. http://dx.doi.org/10.1109/lpt.2012.2183863.

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Schütz, Eckart, Nils Hartmann, Yannis Kevrekidis, and Ronald Imbihl. "Catalysis on microstructured surfaces." Faraday Discuss. 105 (1996): 47–56. http://dx.doi.org/10.1039/fd9960500047.

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Liu, Zhengyong, Hwa-Yaw Tam, Lin Htein, Ming-Leung Vincent Tse, and Chao Lu. "Microstructured Optical Fiber Sensors." Journal of Lightwave Technology 35, no. 16 (August 15, 2017): 3425–39. http://dx.doi.org/10.1109/jlt.2016.2605124.

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Journal articles on the topic 'Microstructured'

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