Articles de revues : « Poly (methyl methacrylate) (PMMA) Thin Films »

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Yuwono, A. H., J. M. Xue, J. Wang, H. I. Elim, Wei Ji, Yuan Yuan Li et T. J. White. « Nonlinear Optical Behavior of Transparent Nanohybrids of Nanocrystalline TiO₂ in Poly(methyl methacrylate) Prepared by In Situ Sol-Gel Polymerization Technique ». Journal of Metastable and Nanocrystalline Materials 23 (janvier 2005) : 367–70. http://dx.doi.org/10.4028/www.scientific.net/jmnm.23.367.

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Nanohybrid thin films consisting of nanocrystalline TiO2 particles in poly(methyl methacrylate)(PMMA) were successfully synthesized by in-situ sol-gel and polymerization assisted by spin coating. Using titanium isoproproxide (Ti-iP), methyl methacrylate (MMA) and 3-(trimethoxysily)propyl methacrylate (MSMA) as the starting materials, nanohybrids containing up to 60% Ti-iP in PMMA were realized. The resulting nanohybrid thin films coated on quartz substrates are optically transparent and demonstrate nonlinear optical behaviour, where their nonlinear absorption increases with the loading of Ti-iP in PMMA, as confirmed by Z-scan measurements. Using pump-probe technique, these thin films are shown to exhibit an ultrafast relaxation time of ~1.5 picosecond.

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Liu, Chih-Ting, Chia-Chan Tsai, Chien-Wei Chu, Mu-Huan Chi, Pei-Yun Chung et Jiun-Tai Chen. « Dewetting of polymer thin films on modified curved surfaces : preparation of polymer nanoparticles with asymmetric shapes by anodic aluminum oxide templates ». Soft Matter 14, n^o 15 (2018) : 2772–76. http://dx.doi.org/10.1039/c8sm00318a.

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Panapoy, M., P. Wannasut et Bussarin Ksapabutr. « Improvement of UV Protection Properties in Poly(Methyl Methacrylate) Sheet Coated by Titanium Dioxide/ Poly(Methyl Methacrylate) Hybrid Film ». Advanced Materials Research 55-57 (août 2008) : 501–4. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.501.

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Titanium dioxide/poly(methyl methacrylate) (TiO2/PMMA) hybrid films with various amounts of TiO2 containing PMMA resin on PMMA sheets were produced by a tape casting method. TiO2 nanocrystals were prepared using electrospraying process at 400oC under high electric field of 3 kV/cm. The as-sprayed and annealed TiO2 powders were characterized by Raman spectroscopy, XRD, SEM and TEM. The UV absorption for both pristine PMMA sheet and TiO2/PMMA hybrid film on PMMA sheet was measured using UV-Vis spectroscopy. The as-sprayed and annealed TiO2 powders showed anatase preferred orientation. They have higher UV absorption in the range of wavelength between 230 and 370 nm than commercial anatase TiO2 nanopowders. Moreover, the visible light transmittances of anatase TiO2/PMMA hybrid films on PMMA sheets in the range of wavelength between 400 and 800 nm was comparable with those derived from pristine PMMA sheets. Therefore, the resulting hybrid films can block out the UV rays, but are transparent to visible light.

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B, Chandar Shekar, Sathisha S, Sulana Sundari, Sunnitha S et Sharmila C. « PREPARATION OF MESOSCOPIC STRUCTURE POLY METHYL METHACRYLATE THIN FILMS FOR AFM DATA STORAGE DEVICES. » Kongunadu Research Journal 2, n^o 1 (4 novembre 2019) : 1–3. http://dx.doi.org/10.26524/krj54.

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Poly methyl methacrylate (PMMA) thin films were prepared by dip coating method. Benzene was used as a solvent to prepare PMMA thin films for the time periods ranging from 1 min. to 1 h. The thickness of the films deposited was measured by using an electronic thickness measuring instrument (Tesatronic-TTD-20). Fourier Transform Infrared spectrum was used to identify the above said films. X-ray diffraction spectra indicated the predominantly amorphous nature of the films. Surface morphology of the coated films studied by using scanning electron microscope (SEM) indicated the absence of any pits, cracks and pin holes in the surface. Both as grown and annealed films showed smooth and amorphous structures. The closer SEM inspection revealed the presence of self assembled mesoscopic cells. The mesoscopic structure PMMA thin films could be used as an AFM-based data storage which is promising alternative to conventional magnetic data storage because it offers great potential for considerable storage density improvements.

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Melo, Lis G. A., Adam P. Hitchcock, Darija Susac, Juergen Stumper et Viatcheslav Berejnov. « Effect of UV radiation damage in air on polymer film thickness, studied by soft X-ray spectromicroscopy ». Physical Chemistry Chemical Physics 20, n^o 24 (2018) : 16625–40. http://dx.doi.org/10.1039/c7cp08621k.

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The thicknesses of thin films of polystyrene (PS), poly(methyl methacrylate) (PMMA), and perfluorosulfonic acid (PFSA) were measured by Ultraviolet Spectral Reflectance (UV-SR) and Scanning Transmission X-ray Microscopy (STXM).

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Mergen, Ömer Bahadır, Ertan Arda et Gülşen Akın Evingür. « Electrical, mechanical, and optical changes in MWCNT-doped PMMA composite films ». Journal of Composite Materials 54, n^o 18 (6 janvier 2020) : 2449–59. http://dx.doi.org/10.1177/0021998319898507.

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In this study, we report the preparation of poly (methyl methacrylate)/multi-walled carbon nanotube (MWCNT) composite thin films by simple and efficient solution mixing and ultrasonic method and the electrical, optical, and mechanical characterizations. Scattered light intensity ( I sc), tensile modulus ( E), and surface conductivity ( σ) of these composites have increased with the addition of MWCNT into the composite. The observed behavior in electrical, optical, and mechanical properties of the poly (methyl methacrylate)/MWCNT composites was interpreted by site and classical percolation theory. The optical mechanical and electrical percolation thresholds of poly (methyl methacrylate)/MWCNT composites were determined as φ op = 3 wt%, φ m = 0 wt%, and φσ = 5 wt%, respectively. The optical ( t op), mechanical ( t m), and electrical ( t σ) critical exponents were calculated as 2.23, 0.43, and 0.11, respectively. Both the tensile modulus and tensile strength of poly (methyl methacrylate)/MWCNT composites were increased with increasing MWCNT content until it reaches to 10 wt%. However, above φ = 10 wt%, the mechanical properties of the composites were decreased due to the aggregation of MWCNTs, while the toughness does not show a significant change until φ = 10 wt% MWCNT content, whereas it was decreased above this value.

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Tippo, Tossapol, Chanchana Thanachayanont, Chabaiporn Junin, Seeroong Prichanont, Micheal Hietschold et Apinunt Thanachayanont. « Effect of Substrates on Preparation of Dissolved PMMA in DMF Solution Used as a Dielectric Layer in Otfts ». Advanced Materials Research 802 (septembre 2013) : 79–83. http://dx.doi.org/10.4028/www.scientific.net/amr.802.79.

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Dissolved Poly (methyl methacrylate) (PMMA) in Dimethylformamide solution was fabricated as thin films on different substrates, glass, poly (ethylene naphthalate) and Si wafer, using spin coating technique. The effect of different substrates on electrical performances of the PMMA films was investigated. For an acceptable organic thin-film transistor (OTFT) performance, uniform thickness with low defect density of the PMMA thin-films was required. A parallel plate capacitor structure was used to test electrical properties of the PMMA dielectric layers. Good dielectric properties were obtained on glass and PEN at film thicknesses of 95 nm. An optimal condition for the OTFT preparation was used to fabricate an OTFT with the PMMA dielectric layer on glass substrate. Measured results showed that the OTFT achieved a mobility of 0.16 cm2/V.s, a threshold voltage of -3.6 V, and on/off current ratio of 1×105.

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Zhao, Dong Lin, Hong Mei Chai, Yun Fang Liu et Zeng Min Shen. « Electrical Resistance Response of Carbon Nanotube / PMMA / PVAc Composite Sensors to Organic Vapours at Low Vapour Concentrations ». Key Engineering Materials 334-335 (mars 2007) : 809–12. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.809.

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Thin films of poly(methyl methacrylate) (PMMA)，poly(vinyl acetate) (PVAc) and carbon nanotube composites were produced by different coating methods. The best way to produce the carbon nanotube / PMMA / PVAc composite film with conductive network is dispersing carbon nanotubes in PMMA and PVAc by ultrasonic and by solution casting. Electrical resistance responses of carbon nanotube / PMMA / PVAc composite sensors against various organic vapors at low concentrations are investigated. The experimental results indicate that the composites have high selectivity to various organic vapors at the same concentration. In addition, the electric resistance response of the composites against organic vapors takes place in step with their vapor adsorption procedure. Compatible blends of poly(methyl methacrylate) and poly(vinyl acetate) would be a good candidate to produce a series of electrically conducting carbon nanotubes composite film whose resistance is sensitive to the nature and concentration of an analyte in the vapor phase. The results indicate that the carbon nanotube / PMMA / PAVc composite film can be used as a novel organic vapor sensor to detect, quantify and discriminate various organic vapors.

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De Nisi, F., R. Francischello, A. Battisti, A. Panniello, E. Fanizza, M. Striccoli, X. Gu, N. L. C. Leung, B. Z. Tang et A. Pucci. « Red-emitting AIEgen for luminescent solar concentrators ». Materials Chemistry Frontiers 1, n^o 7 (2017) : 1406–12. http://dx.doi.org/10.1039/c7qm00008a.

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This study reports for the first time the use of a red-emitting AIEgen, i.e. TPE-AC, for the realization of efficient luminescent solar concentrators (LSCs) based on poly(methyl methacrylate) (PMMA) and polycarbonate (PC) thin films (25 ± 5 μm).

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S. Ali, Ali, Karema M. Zaidan et Adnan Issa Al-Badran. « Preparation of Poly (methyl methacrylate) thin film Capacitors on ITO-glass substrate ». Muthanna Journal of Pure Science 9, n^o 2 (31 décembre 2022) : 22–28. http://dx.doi.org/10.52113/2/09.02.2022/22-28.

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In electronic devices, some important materials having a high dielectric constant can be used. Polymer-ceramic composites have a high dielectric constant and are widely used for embedded capacitor applications. It is critical to use polymer poly methyl methacrylate (PMMA) as thin films capacitors for the gate dielectric in organic field-effect transistors (OFETs). In this work, thin films of polymer PMMA were prepared by using spin coating at different speeds (1500, 2000, 2500, 3000 and 3500 rpm) to control the film thickness and study the effect of the thickness on the dielectric properties. Thin film thickness was measured by using field emission scanning electron microscopy (FESEM) to take cross-section images. We found that the film thickness decreased with increased rotational speed from 27387 nm at 1500 rpm to 10600 nm at 3500 rpm. The values of the capacities were nearly stable with increasing frequencies when thickness equal to or larger than (14366 nm), but their increased with increased frequency at thickness (10600 nm), and the dielectric constant also decreases with increasing thin films thickness. The best result of capacitance value was at thickness 10600nm which equal to (5.753 nF) and dielectric constant equal to (3.511) which represents best value that can be used as dielectric gate for Organic Field Effect Transistor (OFET).

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Salih, Mohammed H., Mohammed Hadi Shinen et Maan A. Saleh. « Investigating the Impact of Doping Ratios on the Optical Features of Poly (Methyl Methacrylate) ». NeuroQuantology 20, n^o 3 (26 mars 2022) : 216–23. http://dx.doi.org/10.14704/nq.2022.20.3.nq22063.

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Using spin-coating method, the poly (methyl methacrylate) (PMMA)/multi-walled carbon nanotubes (MWCNTs) thin films are prepared. The optical features from the band gap, refractive index and optical connectivity are studied. The gap was calculated from the UV-Vis spectra. The superficial structure is examined through the use of the atomic force microscope (AFM) to investigate the dispersion of MWCNT within the polymer matrix.

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Reddy Mettu, Maheshwar, A. Mallikarjun, M. Jaipal Reddy et J. Siva Kumar. « INVESTIGATION OF PMMA AND PVdF-HFP WITH NaClO4POLYMER BLEND ELECTROLYTE SYSTEM– APPLICATION TO AN ELECTROCHEMICAL CELL ». RASAYAN Journal of Chemistry 15, n^o 03 (2022) : 2188–96. http://dx.doi.org/10.31788/rjc.2022.1536956.

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A solution-cast process was used to prepare pure poly (methyl methacrylate) (PMMA), and pure poly (vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), their blend, and different weight percentages of sodium per chlorate (NaClO4) salt added to PMMA: PVdF-HFP polymer blend electrolyte thin films. The polymer electrolyte film was prepared using the solution cast process, which involves combining sodium per chlorate (NaClO4) ionic slat with poly (methyl methacrylate) (PMMA) and pure poly (vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) blended polymer. These films have been characterized systematically using different experimental techniques to investigate structural, morphological, thermal, and conductivity properties. The degree of crystallinity and porous microstructure of all the thin films were determined by XRD and SEM data and revealed that higher content of the amorphous nature was noticed at higher NaClO4 salt concentration in PMMA:PVdF-HFP polymer blend. When NaClO4 salt was added to a PMMA:PVdF-HFP polymer blend, fair complexation/interaction between polymers and salt was observed.In DSC curves of PMMA and PVdF-HFP polymers, a sharp melting temperature (Tm) was seen, which diminished when NaClO4 salt was added, showing that its amorphous nature had risen to prominence. The ionic conductivity of NaClO4 salt added PMMA:PVdF-HFP polymer blend electrolyte has been investigated, with an optimal value found to be1.55382 x 10-4S/cm at 40% NaClO4 salt. Electrochemical cells have been fabricated and investigated its characteristics in the configuration of Na/[PMMA:PVdF-HFP: NaClO4]/(I2:C).

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Mahdi, Bashair S., et Safaa A. Hasson. « Linear Optical Characterization of Novel Dye Doped Poly Methyl Methacrylate with Titanium Dioxide Nanoparticale ». NeuroQuantology 19, n^o 1 (18 février 2021) : 16–21. http://dx.doi.org/10.14704/nq.2021.19.1.nq21003.

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The project includes preparation of organic dyes as powder, pure dyes as thin film, pure dyes doped with Poly methyl methacrylate (PMMA) and pure dyes doped PMMA with titanium dioxide nanoparticles (TiO2) to study the linear optical properties. Organic dyes (pure and doped) are interesting materials for linear optical properties and its applications because of their high response linearity and their extended spectral transparency. In this work, preparation organic compound dyes (Schiff bases) derived fromclosed ring were carried out as thin films of materials have been deposited on glass substrates. The samples prepared in for concentrations (10-4 and 10-5) M and thin films were deposited via drop casting.

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Priestley, Rodney D., Manish K. Mundra, Nina J. Barnett, Linda J. Broadbelt et John M. Torkelson. « Effects of Nanoscale Confinement and Interfaces on the Glass Transition Temperatures of a Series of Poly(n-methacrylate) Films ». Australian Journal of Chemistry 60, n^o 10 (2007) : 765. http://dx.doi.org/10.1071/ch07234.

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We use fluorescence from dye-labelled polymer to measure the glass transition temperatures (Tgs) across single-layer films and near surfaces and silica interfaces in bilayer films for a series of poly(n-methacrylate)s. With nanoscale confinement, the average Tg across a film supported on silica increases for poly(methyl methacrylate) (PMMA), decreases for poly(ethyl methacrylate) (PEMA) and poly(propyl methacrylate), and is nearly invariant for poly(iso-butyl methacrylate) (PIBMA). These trends are consistent with the relative strengths of local perturbations to Tg caused by surfaces and substrates as measured in bilayer films. The substrate effect, which increases Tg via hydrogen-bonding interactions between the polymer and hydroxyl groups on the silica surface, is stronger than the free-surface effect in PMMA. The free-surface effect, which reduces Tg via a reduction in the required cooperativity of the glass transition dynamics, is stronger than the substrate effect in PEMA. The substrate and free-surface effects have similar strengths in perturbing the local Tg in PIBMA, resulting in a net cancellation of effects when measurements are made across single-layer films.

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García, Dennis Cabrera, José Enrique Eirez Izquierdo, Vinícius Augusto Machado Nogueira, José Diogo da Silva Oliveira, Marco Roberto Cavallari, Alain A. Quivy et Fernando Josepetti Fonseca. « Organic Dielectric Films for Flexible Transistors as Gas Sensors ». Journal of Integrated Circuits and Systems 15, n^o 2 (31 juillet 2020) : 1–7. http://dx.doi.org/10.29292/jics.v15i2.170.

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Cross-linked polymer films with poly(melamine-co-formaldehyde) methylated (PMF) were investigated in order to integrate flexible organic transistor-based sensors. By blending poly(methyl methacrylate) (PMMA) with PMF, solutions showed reduced viscosity for wet processing. Thin-films from poly (4-vinylphenol) (PVP) blends with PMF featured lower RMS roughness (0.37 nm) and higher dielectric constant (k ~ 3.7 – 5.7). The presence of enhanced cross-linking at higher PMF concentrations was confirmed for both polymers from chemical resistance essays and structural characterization.

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Najim, Manar Abd, Akram Raheem Jabur et Ali A. Hameed. « Effect of Iodine Addition on Improving the Electrical Conductivity and Activation Energy of Electrospun PMMA Thin Films ». Materials Science Forum 1002 (juillet 2020) : 84–94. http://dx.doi.org/10.4028/www.scientific.net/msf.1002.84.

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Conductive polymer films were prepared from poly (methyl methacrylate) PMMA with (0, 0.3, 0.5, 0.7, and 0.9) wt. % of iodine, using electrospinning technique. A decrease was noticed in the polymer solution viscosity with increasing the iodine weight percentage while both surface tension and electrical conductivity of the polymer solutions were increased .The structure and morphology of the prepared films were characterized by scanning electron microscopy SEM, the average fiber diameter measured statistically from the SEM images and was equal to 800 nm for PMMA with 0.7 wt. % iodine thin film, and 400 nm for the pure PMMA thin film. The electrical conductivity was enhanced for the electrospun films with increasing iodine concentration, from (29.5518× 10-9 S/cm) for pure PMMA film to (59.3725× 10-9 S/cm) for PMMA with 0.9 wt. % of iodine additives at room temperature. Activation energy decreased from 0.4483 e.V for pure PMMA to 0.43029 e.V for PMMA with 0.9 wt. % iodine.

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Jehnichen, Dieter, Doris Pospiech, Andreas Berndt, Selina C. Gomoll, Eva Natkowski et Matthias Plötner. « X-ray characterization of crosslinked methacrylate copolymers for application as dielectric layers in organic electronics ». Powder Diffraction 34, S1 (25 juillet 2019) : S71—S81. http://dx.doi.org/10.1017/s0885715619000502.

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Poly(methyl methacrylate) (PMMA) is one of the most important polymers for application as a dielectric layer in organic electronics, e.g. in organic field-effect transistors. The key to improve the transistor performance is the optimization of the interface between the semiconductor and the dielectric layer. Here, the surface order in thin films of PMMA copolymers with self-organized, semifluorinated (sf) building blocks, and crosslinkable units in single layers and double layers with poly(3-hexylthiophene-2,5-diyl) (P3HT) is investigated. The chemistry of the sf copolymers is systematically varied and the influence on the self-organization in bulk and thin films is examined by a combination of scattering methods. The length of the semifluorinated side chains mainly determines the degree and type of order both in bulk as well as in thin films.

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Gianfaldoni, Federico, Francesca De Nisi, Giuseppe Iasilli, Annamaria Panniello, Elisabetta Fanizza, Marinella Striccoli, Daiki Ryuse, Masaki Shimizu, Tarita Biver et Andrea Pucci. « A push–pull silafluorene fluorophore for highly efficient luminescent solar concentrators ». RSC Advances 7, n^o 59 (2017) : 37302–9. http://dx.doi.org/10.1039/c7ra08022k.

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We report on the preparation of luminescent collectors based on poly(methyl methacrylate) (PMMA) thin films doped with a red-emitting 2-amino-7-acceptor-9-silafluorene, where the amino group is –N(CH₃)₂and the acceptor is –CHC(CN)₂.

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Yoon, Jinhwan, Seung Yun Yang, Byeongdu Lee, Wonchul Joo, Kyuyoung Heo, Jin Kon Kim et Moonhor Ree. « Nondestructive quantitative synchrotron grazing incidence X-ray scattering analysis of cylindrical nanostructures in supported thin films ». Journal of Applied Crystallography 40, n^o 2 (12 mars 2007) : 305–12. http://dx.doi.org/10.1107/s0021889807000817.

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Nondestructive nanostructural analysis is indispensable in the development of nanomaterials and nanofabrication processes for use in nanotechnology applications. This paper demonstrates a quantitative, nondestructive analysis of nanostructured thin films supported on substrates and their templated nanopores by using grazing incidence X-ray scattering and data analysis with a derived scattering theory. The analysis disclosed that vertically oriented nanodomain cylinders had formed in 20–100 nm thick films supported on substrates, which consisted of a mixture of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and PMMA homopolymer, and that the PMMA nanodomain cylinders were selectively etched out by ultraviolet light exposure and a subsequent rinse with acetic acid, resulting in a well ordered nanostructure consisting of hexagonally packed cylindrical nanopores.

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B, Chandar Shekar, Ranjit Kumar R, Dinesh K.P.B, Sulana Sundari C et Punithavathi K. « PREPARATION OF POLY (METHYL METHACRYLATE) THIN FILMS BY SPIN COATING TECHNIQUE FOR OTFT AND WOUND HEALING APPLICATIONS ». Kongunadu Research Journal 5, n^o 1 (30 juin 2018) : 20–22. http://dx.doi.org/10.26524/krj246.

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Thin films of poly (methyl methacrylate) (PMMA) were prepared on cleaned glass slides by using spin coating technique. The prepared films were identified by using FTIR spectrum. Surface morphology of the coated films was studied by using SEM and AFM. Both as grown and annealed films showed smooth and amorphous structure. It also revealed the absence of pits, pin holes and dendritic features in the surface. Both as grown and annealed films showed very low RMS roughness value. The morphology analysis revealed that the prepared film could be used as dielectric layer in thin film transistors and as drug delivery system forwound healing.

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Jehnichen, Dieter, Doris Pospiech, Peter Friedel, Andriy Horechyy, Andreas Korwitz, Andreas Janke, Franziskus Näther, Christine M. Papadakis, Jan Perlich et Volker Neu. « Effects of nanoparticles on phase morphology in thin films of phase-separated diblock copolymers ». Powder Diffraction 32, S1 (30 janvier 2017) : S141—S150. http://dx.doi.org/10.1017/s0885715616000762.

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This study investigates the morphology changes in thin diblock copolymer (DiBCP) films occurring in the interaction with modified nanoparticles (NPs). Magnetite (Fe3O4) and silica (SiOx) were prepared and used. Poly(pentyl methacrylate-b-methyl methacrylate) (PPMA-b-PMMA) (70/30 mol mol−1, hcp cylinders of the PMMA phase) DiBCP were employed to prepare thin films having thicknesses to realize standing cylinders in pure DiBCP films. The investigations aimed at two topics: (1) morphology after controlled incorporation of organo-modified NP (gold, silver, Fe3O4, SiOx) and (2) additional solvent vapour annealing (SVA) with tetrahydrofuran (and chloroform for comparison). The laterally ordered morphology in thin films was examined by GISAXS and atomic force microscopy. Keeping the same type of morphology in nanocomposites, the dimensions of the periodic nanostructure altered depending on type and amount of incorporated NP. It was found that SiOx clusters enlarge the lateral distance of the PMMA cylinders, whereas metallic NPs reduce this parameter. Applying SVA improves the phase separation slightly, whereas lateral distances were kept constant or were reduced a little. Switching of domain orientation upon SVA could not be detected in the presence of NPs located at the polymer/substrate interface.

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Abdullah, Nadhim A., et Fatima H. Malk. « Optical Properties of Blend of PMMA:PVDF ». University of Aden Journal of Natural and Applied Sciences 25, n^o 1 (22 mars 2022) : 189–96. http://dx.doi.org/10.47372/uajnas.2021.n1.a16.

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In this study, thin films of PMMA Poly (methyl methacrylate)- Polyvinylidene fluoride(PMMA-PVDF), PMMA polymer and soluble PVDF polymer were prepared at (5%)Toluene and polymeric blends in 1:1 volume ratio of polymers and in different proportions of polymers. The studied films were prepared by the Spin coating method, and the optical parameters of the thin films were measured within a range (300-900)nm and the thickness of the films were constant (223 nm). Absorbance (A), linear absorption coefficient (α), refractive index (n), extinction coefficient (K), real and imaginary dielectric constant (∈r, ∈i), and optical energy gap Eg were studied, as the best edge of optical absorption was 5% PVDF, And electronic transmission between levels was direct transmission.

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Yadigarli, Aydan, Qimeng Song, Sergey I. Druzhinin et Holger Schönherr. « Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red ». Beilstein Journal of Organic Chemistry 15 (25 octobre 2019) : 2552–62. http://dx.doi.org/10.3762/bjoc.15.248.

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The permittivity of polymers and its spatial distribution play a crucial role in the behavior of thin films, such as those used, e.g., as sensor coatings. In an attempt to develop a conclusive approach to determine these quantities, the polarity of the model polymer poly(methyl methacrylate) (PMMA) in 600 nm thin films on a glass support was probed by the energy of the charge transfer transition in the oxazine dye Nile red (NR) at 25 °C. The absorption and fluorescence spectra of NR were observed to shift to the red with increasing solvent polarity, because of the intramolecular charge transfer character of the optical transition. New types of solvatochromic plots of emission frequency against absorption frequency and vice versa afforded the Onsager radius-free estimation of the ground and excited states dipole moment ratio. With this approach the values of these dipole moments of 11.97 D and 18.30–19.16 D, respectively, were obtained for NR. An effective local dielectric constant of 5.9–8.3 for PMMA thin films was calculated from the solvatochromic plot and the fluorescence maximum of NR observed in the PMMA films. The fluorescence band of NR in the rigid PMMA films shifted to the red by 130 cm−1 with increasing excitation wavelength from 470 to 540 nm, while in a series of liquids the position of the emission maximum of NR remained constant within same range of the excitation wavelength. It is concluded that the fluorescence spectrum of NR in PMMA undergoes inhomogeneous broadening due to different surroundings of NR molecules in the ground state and slow sub-glass transition (T g) relaxations in PMMA.

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Mukdachacharoenchai, P., Wanichaya Mekprasart, J. Sritharathikhun et Wisanu Pecharapa. « Effect of TiO₂ Compact Layer on Optical Absorption and Fluorescence Performance of R6G/PMMA Composite Light - Guided Films ». Advanced Materials Research 528 (juin 2012) : 245–48. http://dx.doi.org/10.4028/www.scientific.net/amr.528.245.

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Rhodamine 6G (R6G) and Poly(methyl methacrylate) (PMMA) light-guided films accompanied with titanium dioxide thin layer were prepared by spin-coating process onto on glass substrate. Dichloromethane was used as disperser for blending R6G and PMMA. The TiO2 layer thickness was varied by controlling spinning speed. The effects of TiO2 layer with different thickness on optical absorption and florescence performance of the films were investigated and the results exhibited strong absorption of TiO2 in UV region and the enhancement in florescence efficiency with increasing TiO2 film thickness.

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Fujita, Masato, Naokazu Idota, Kimihiro Matsukawa et Yoshiyuki Sugahara. « Preparation of Oleyl Phosphate-Modified TiO2/Poly(methyl methacrylate) Hybrid Thin Films for Investigation of Their Optical Properties ». Journal of Nanomaterials 2015 (2015) : 1–7. http://dx.doi.org/10.1155/2015/297197.

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TiO2nanoparticles (NPs) modified with oleyl phosphate were synthesized through stable Ti–O–P bonds and were utilized to prepare poly(methyl methacrylate)- (PMMA-) based hybrid thin films via theex situroute for investigation of their optical properties. After surface modification of TiO2NPs with oleyl phosphate, IR and13C CP/MAS NMR spectroscopy showed the presence of oleyl groups. The solid-state31P MAS NMR spectrum of the product revealed that the signal due to oleyl phosphate (OP) shifted upon reaction, indicating formation of covalent Ti–O–P bonds. The modified TiO2NPs could be homogeneously dispersed in toluene, and the median size was 16.1 nm, which is likely to be sufficient to suppress Rayleigh scattering effectively. The TEM images of TiO2/PMMA hybrid thin films also showed a homogeneous dispersion of TiO2NPs, and they exhibited excellent optical transparency even though the TiO2content was 20 vol%. The refractive indices of the OP-modified TiO2/PMMA hybrid thin films changed higher with increases in TiO2volume fraction, and the hybrid thin film with 20 vol% of TiO2showed the highest refractive index (n = 1.86).

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Gong, Yu Mei, Ying Xin He, Jing Guo et Hong Zhang. « A Concise Route to Fabricate TiO₂ Nanoporous and Nanopillar Films Based on Block Copolymer Self-Assembly ». Advanced Materials Research 774-776 (septembre 2013) : 931–34. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.931.

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This study developed a concise route to fabricate TiO2 nanoporous and nanopillar films based on the self-assembly of block-copolymer thin films in periodic nanostructures. We obtained the perpendicularly oriented cylindrical domains in polystyrene-b-poly (methyl methacrylate) (PS-b-PMMA) diblock copolymer (BCP) films by thermal annealing on ITO substrate modified by a cross-linkable random copolymer, and then these films were immersed into the titanium oxide sol in acetic acid for a few hours. The acetic acid in the sol can selectively swell the PMMA component, which results in titanium oxide sol being loaded to the PMMA component selectively. Then the films were calcined at high temperature to remove the PS-b-PMMA block copolymer, and simultaneously the titanium oxide was transferred in situ to the substrate. As a result, a highly ordered array of nanoporous and nanopillar TiO2 thin film is observed on the ITO substrates depending upon the block copolymer used with PS and PMMA cylinder-forming components. In principle, it can be a general and versatile approach for fabricating functional nanoparticle arrays.

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Chen, Jiayao, Jing Li, Lirong Xu, Wei Hong, Yuzhao Yang et Xudong Chen. « The Glass-Transition Temperature of Supported PMMA Thin Films with Hydrogen Bond/Plasmonic Interface ». Polymers 11, n^o 4 (2 avril 2019) : 601. http://dx.doi.org/10.3390/polym11040601.

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The interfacial effect is one of the significant factors in the glass-transition temperature (Tg) of the polymeric thin film system, competing against the free surface effect. Herein, the Tgs of poly (methyl methacrylate) (PMMA) films with different thicknesses and substrates are studied by fluorescence measurements, focusing on the influence of interfacial effects on the Tgs. The strong interaction between PMMA and quartz substrate leads to increased Tgs with the decreased thickness of the film. The plasmonic silver substrate causes enhanced fluorescence intensity near the interface, resulting in the delayed reduction of the Tgs with the increasing film thickness. Moreover, as a proof of the interface-dependent Tgs, hydrogen bonds of PMMA/quartz and molecules orientation of PMMA/silver are explored by the Raman spectroscopy, and the interfacial interaction energy is calculated by the molecular dynamics simulation. In this study, we probe the inter-relationship between the interfacial interactions arising from the different substrates and the Tg behavior of polymer thin films.

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Khan, Mohammad Saleem, Rahmat Gul et Mian Sayed Wahid. « Studies on thin films of PVC-PMMA blend polymer electrolytes ». Journal of Polymer Engineering 33, n^o 7 (1 octobre 2013) : 633–38. http://dx.doi.org/10.1515/polyeng-2013-0028.

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Abstract Thin films of poly (vinyl chloride) (PVC)/poly (methyl methacrylate) (PMMA) blend polymers complexed with different concentrations of LiClO4 salt, containing ethylene carbonate (EC) as the plasticizer, were fabricated by the solution cast procedure. Ionic conductivity, thermal stability and X-ray diffraction (XRD) studies were undertaken. AC impedance measurements were done in the temperature range of 20–70°C. The highest ionic conductivity at room temperature was found to be 2.23×10-5 S cm-1 for the sample containing 15 wt% of LiClO4 salt. The XRD technique was used to investigate the structure and complex formation of solid polymer electrolytes. There was a decrease in degree of crystallinity. The amorphous nature of complexed solid polymer blend electrolyte films increased, due to the addition of LiClO4 salt. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) revealed the effect of salt on the thermal stability of the polymer electrolytes. It was found that these polymer electrolyte systems show stability up to about 280°C. It was also found that, with increased LiClO4 salt content in complexed polymer electrolyte systems, the degradation temperature decreased.

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Sansul, Shaymaa, Emad Yousif, Dina S. Ahmed, Gamal A. El-Hiti, Benson M. Kariuki, Hassan Hashim et Ahmed Ahmed. « Pendant Modification of Poly(methyl methacrylate) to Enhance Its Stability against Photoirradiation ». Polymers 15, n^o 14 (9 juillet 2023) : 2989. http://dx.doi.org/10.3390/polym15142989.

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Photostabilization of functional polymeric materials is important for protection against aging and ultraviolet (UV) irradiation. There is, therefore, the impetus to modify polymers to increase their resistance to photodegradation and photooxidation on extended exposure to UV light in harsh conditions. Various polymeric additives have been designed and synthesized in recent years, and their potential as photostabilizers has been explored. Reported here is the effect of pendant functionalization of poly(methyl methacrylate) (PMMA) through organometallic moiety incorporation into the polymer’s backbone. The reaction of PMMA with ethylenediamine leads to the formation of an amino residue that can react with salicylaldehyde to produce the corresponding Schiff base. Adding metal chlorides (zinc, copper, nickel, and cobalt) led to the formation of organometallic residues on the polymeric chains. Thin films of modified and unmodified PMMA were produced and irradiated with UV light to determine the effect of pendant modification on photostability. The photostabilization of PMMA was assessed using a range of methods, including infrared spectroscopy, weight loss, decomposition rate constant, and surface morphology. The modified PMMA incorporating organic Schiff base metal complexes showed less photodecomposition than the unmodified polymer or one containing the Schiff base only. Thus, the metals significantly reduced the photodegradation of polymeric materials. The polymer containing the Schiff base-cobalt unit showed the least damage in the PMMA surface due to photoirradiation, followed by those containing nickel, zinc, and copper, in that order.

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Xu, Jinku, et Dongmei Li. « Preparation and Photoluminescence of Transparent Poly(methyl methacrylate)-Based Nanocomposite Films with Ultra-High-Loading Pendant ZnS Quantum Dots ». Polymers 10, n^o 11 (2 novembre 2018) : 1217. http://dx.doi.org/10.3390/polym10111217.

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Transparent nanocomposite films containing quantum dots are popular because of their extensive applications. However, nanoparticles tend to aggregate, resulting in phase separation of the nanoparticles in the polymer matrix. Herein, we present a bulk thermo-curing copolymerization method to fabricate poly(methyl methacrylate)-based nanocomposite films with ultra-high-loading ZnS quantum dots (ZnS/PMMA), utilizing polymerizable group-capped ZnS and monomer of methyl methacrylate (MMA). We found that the nanocomposite film is highly transparent, although the transmittance decreases with the ZnS content, especially at the wavelength between 300 nm and 400 nm. The results from X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic mechanical thermal analysis (DMTA) show that the ZnS quantum dots maintain their original crystal structure, and are uniformly dispersed in the nanocomposite films, even with a very high ZnS content (41 wt %, determined by thermogravimetric analysis). The thermogravimetric analysis shows that the nanocomposite films possess a better thermal stability than that of pure PMMA film. The photoluminescence measurements show that ZnS/PMMA nanocomposite films have good optical properties. The fluorescence intensity increases with the increment of free ZnS content to 30 wt %, and then decreases due to self-reabsorption at a higher ZnS content. The transparent ZnS/PMMA nanocomposite films have a potential application as photoluminescence material.

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Al-Hamdani, Ali H. « Studying the spectral properties of thin films of rhodamine (6G) dyes doped polymer (PMMA) dissolved in chloroform ». Iraqi Journal of Physics (IJP) 12, n^o 23 (18 février 2019) : 59–64. http://dx.doi.org/10.30723/ijp.v12i23.339.

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In the present work, poly methyl methacrylate (PMMA) doped with Rhodamine 6G was prepared. The spectral properties (absorption and fluorescence) of the films were studied at different concentrations (1x10-5, 2x10-5, 5x10-5, 7x10-5, and 1x10-4mol/l). The investigated samples were made in the form of thin films. This was achieved by dissolving a certain weight of PMMA in a fixed volume of chloroform, composite films was with thickness (25.8μm) at room temperature. The achieved results were pointed out that absorption and fluorescence spectra have taken a wide spectral rang so when increased the concentration each peak shift toward along wavelength. The quantum efficiency of the films were calculated as follows (98%,89%,84%,83% and 76%) for the above concentrations respectively. It has been noticed that the quantum efficiency decreases as the concentrations increases.

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Almusawe, A. J., F. A. Nuha et Salah M. Abdul Aziz. « Optical Properties of Sudan Black Stain Doped PMMA Thin Films at Different Concentration and Gamma Irradiation Effect ». NeuroQuantology 20, n^o 3 (29 mars 2022) : 237–45. http://dx.doi.org/10.14704/nq.2022.20.3.nq22066.

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In this paper, the optical properties investigated and the effect of the gamma irradiation on the optical constant in addition to the energy band gap (Eg) of Sudan black stain doped Poly Methyl Methacrylate (PMMA) thin films. Thin films of 20% Sudan black stain/PMMA doping ratio was used to prepared three concentrations (1, 0.7, 0.4) x10-3 M. all the Dye/ Polymer solution (three different concentrations) deposited on glass substrate by using a free casting method at room temperature. The UV-Visible absorbance and transmittance spectra at the 300 - 800 nm wavelength range were used to investigate the optical properties of the films. The optical constant such as linear absorption coefficient, the extinction coefficient, and Eg were calculated. Results showed an increasing in the optical properties after irradiation with γ rays with activity 16 gray/hour, while Eg was decreasing after irradiation.

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Her, Hyun-Jung, Jung-Min Kim, C. J. Kang et Yong-Sang Kim. « Fabrication of Thin Film Titania with Nanopores, Nanopoles, and Nanopipes by Nanoporous Alumina Template ». Journal of Nanoscience and Nanotechnology 8, n^o 9 (1 septembre 2008) : 4808–12. http://dx.doi.org/10.1166/jnn.2008.ic84.

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We demonstrate the formation of thin film titania (TiO2) with a dense array of nanopores, nanopoles, and nanopipes. The heights of pores, poles, and pipes were approximately 130 nm, 180 nm, and 200 nm, respectively. The aspect ratios of these three structures were approximated between 2 and 3. In order to obtain titania thin films, a nanoporous alumina (Al2O3) template was fabricated by performing a two-step anodization process. The spin-coated titania films were uniformly patterned by a nanoimprinting lithography technique with a textured poly(methyl methacrylate) (PMMA) mold or nanoporous alumina template. The titania films are very useful for solar cells, photocatalytic and sensing applications, in which nano-structuring of surfaces with controlled dimensions is vital.

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Jin, Sil Ro, et Jong Keun Lee. « Isothermal Physical Aging of Poly(ethyl methacrylate)/Polyhedral Oligomeric Silsequioxanes Nanocomposite Thin Films ». Advanced Materials Research 287-290 (juillet 2011) : 2234–39. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2234.

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The effects of the polyhedral oligomeric silsequioxanes (POSS) in stacked poly(methyl methacrylate) (PMMA) film samples were investigated in two different film thicknesses, ~50 and ~660 nm. The types of the POSS include methacryl-, octaisobutyl-, and octasilane-POSS. The glass transition temperature (Tg) and isothermal physical aging was depressed by the reduction of film thickness. Among POSS molecules used in this work, methacryl-POSS was the greatest effect in both Tgand relaxation enthalpy (DHRelax) due to the physical aging. The Kohlrausch-Williams-Watts (KWW) relaxation function was used to further understand the effect of POSS and film thickness on the physical aging.

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Zailani, N. A. M., F. A. Latif, Z. S. M. Al Shukaili, Pramod K. Singh, S. F. M. Zamri et M. A. A. Rani. « Ionic Liquid Encapsulated Poly (Methyl Methacrylate) Electrolyte Film in Electrical Double Layer Capacitor ». International Journal of Emerging Technology and Advanced Engineering 12, n^o 11 (1 novembre 2022) : 89–97. http://dx.doi.org/10.46338/ijetae1122_10.

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One of the main components of electrical double layer capacitor (EDLC) is the electrolyte. Gel-type electrolyte has shown good performance in EDLC. However, not much information is available on film-type electrolytes, which are known to provide better mechanical stability than the gel-type electrolyte. In present study, we have reported the performance of film-type poly(methyl methacrylate (PMMA) as electrolyte in electrical double layer capacitor (EDLC) systems and compared with the gel-type PMMA electrolytes. This film-type PMMA electrolyte is modified by encapsulating 1-methyl-3-pentamethyldisiloxymethylimidazolium bis (trifluoromethylsulfonyl)imide, [(SiOSi)C1C1 im][NTf2 ], an ionic liquid (IL), into the PMMA matrix, PMMAIL. Doping this PMMAIL film with 30% lithium triflate salt (LiTf), LiTfPMMAIL, provides an EDLC cell with higher breakdown voltage (3.2 V) and higher specific discharge capacity (Csp) (6.59 Fg-1 ) and energy density (0.92 Whkg-1 ) than the selected PMMA-based gel electrolyte systems. These values exceed the minimum requirements for a working supercapacitor. However, this LiTF-PMMAIL cell exhibited lower power density (23.04 Wkg-1 ) than the selected EDLC cells due to the more congested system of LiTF-PMMAIL. Thus, the performance of this LiTF-PMMAIL cell could be improved by adjusting the amount of doping salt and using different types of carbon electrodes. Keywords—capacitors, charging/discharging, polymer electrolyte films, poly (methyl methacrylate) electrolytes, solid electrolytes.

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Jayaraman, Akhila, Gayathri Subramanyam, Swaminathan Sindhu, Parayil Kumaran Ajikumar et Suresh Valiyaveettil. « Biomimetic Synthesis of Calcium Carbonate Thin Films Using Hydroxylated Poly(methyl methacrylate) (PMMA) Template ». Crystal Growth & ; Design 7, n^o 1 (janvier 2007) : 142–46. http://dx.doi.org/10.1021/cg060172t.

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Aziz, Aadila, N. A. M. Asib, A. N. Afaah, R. Mohamed, Mohamad Rusop et Zuraida Khusaimi. « Structural and Optical Properties of ZnO/PMMA Nanocomposite ». Advanced Materials Research 832 (novembre 2013) : 602–6. http://dx.doi.org/10.4028/www.scientific.net/amr.832.602.

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UV filter is an interesting and challenging application in industries. Hence, ZnO-PMMA nanocomposite thin films have been chosen to achieve above mentioned characteristics [1]. In this study, fabrication of ZnO on PMMA glass substrate successfully prepared by using the solution-immersion method. Layer by layer of poly (methyl methacrylate) (PMMA) was deposited on a glass substrate using the spin coating technique by dissolving PMMA in toluene. Various layers of PMMA were varied to 1, 3, 5 and 7 layers. The structural and optical properties of ZnO/PMMA nanocomposite were then characterized by Field Emission Scanning Electron Microscope (FESEM) and Photoluminescene (PL) Spectroscopy. From FESEM result, shape of nanorod unclearly seen as the layer deposited of PMMA increase and from EDAX show oxygen element have highest atomic percentage 65.50 %. 7 layer of deposited PMMA show highest intensity compare to other layers in green region at 577.32 nm for PL measurement.

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Guan, Xiao Lin, Hong Ting Fan, Dong Hai Zhang, Yang Zhang, Tian Ming Jia et Shou Jun Lai. « Covalent Binding of CdSe@PMMA Nanocomposite Films with both Good Transparency and UV-Shielding ». Journal of Nano Research 41 (mai 2016) : 42–52. http://dx.doi.org/10.4028/www.scientific.net/jnanor.41.42.

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Thin UV-blocking films of poly(methyl methacrylate) and CdSe quantum dots (QDs) (CdSe@PMMA) are built up by CdSe-azo initiator through surface-initiated free-radical polymerization. CdSe@PMMA nanocomposite film possesses excellent transparency and ultraviolet (UV)-shielding properties. The average size of CdSe QDs is found to be less than 5 nm and well dispersed in the PMMA matrices without any significant agglomeration by the transmission electron microscopy (TEM) measurement. At the same time, excellent fluorescence (FL) spectra of the nanocomposite indicate that the luminescent properties of CdSe QDs remain effective after the polymerization. Such the transparent and luminescence CdSe@PMMA nanocomposite film exhibits prominent UV-absorbing capability and the high optical transparency in the visible-wavelength region, thus make it to be a promising material for the large scale fabrication of diverse optical devices.

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Ghandhe, Anita Rajkumar, et Basavaraja Sannakki. « The Mechanical Properties of Poly(Methyl Methacrylate) (PMMA)/ZrO2 Nanocomposite Polymer Films ». Advanced Science Letters 24, n^o 8 (1 août 2018) : 5614–17. http://dx.doi.org/10.1166/asl.2018.12161.

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The composite films of Polymethylmethacrylate (PMMA) with ZrO2 at different weight percentage have been used for measurement of Mechanical properties such as stress, strain, and Young’s modulus at room temperature using the Universal Testing Machine. The value of stress is increased linearly with strain up to the stress at break and afterwards shown discontinuity. The properties of stress and strain increased as weight percentage of ZrO2 increased with PMMA and at 60 weight percent the stress in increased linearly up to 2.18 MPa with strain. The tensile strength, load at break and stress at break of the composite film of PMMA with ZrO2 is increased as weight percentage increased. Further, the weight loss and melting temperature of the composite films for pristine and for irradiation by electron beam at dose rate of 100 kGy were measured using Thermo Gravimetric Analysis and Differential Scanning Calorimeter. The weight loss of the composite film after electron irradiation is higher than that of its pristine. It is observed from DSC that melting peak is occurred at temperature 397.52 °C for pristine and at 395.94 °C after electron irradiation. Hence change in melting temperature is found to be 1.58 °C. The prepared composite films are characterized by using FTIR over the range of 3500– 500 wavenumbers (cm−1).

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Ali, Alaa Y., Natalie P. Holmes, Mohsen Ameri, Krishna Feron, Mahir N. Thameel, Matthew G. Barr, Adam Fahy et al. « Low-Temperature CVD-Grown Graphene Thin Films as Transparent Electrode for Organic Photovoltaics ». Coatings 12, n^o 5 (16 mai 2022) : 681. http://dx.doi.org/10.3390/coatings12050681.

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Good conductivity, suitable transparency and uniform layers of graphene thin film can be produced by chemical vapour deposition (CVD) at low temperature and utilised as a transparent electrode in organic photovoltaics. Using chlorobenzene trapped in poly(methyl methacrylate) (PMMA) polymer as the carbon source, growth temperature (Tgrowth) of 600 °C at hydrogen (H2) flow of 75 standard cubic centimetres per minute (sccm) was used to prepare graphene by CVD catalytically on copper (Cu) foil substrates. Through the Tgrowth of 600 °C, we observed and identified the quality of the graphene films, as characterised by Raman spectroscopy. Finally, P3HT (poly (3-hexylthiophene-2, 5-diyl)): PCBM (phenyl-C61-butyric acid methyl ester) bulk heterojunction solar cells were fabricated on graphene-based window electrodes and compared with indium tin oxide (ITO)-based devices. It is interesting to observe that the OPV performance is improved more than 5 fold with increasing illuminated areas, hinting that high resistance between graphene domains can be alleviated by photo generated charges.

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Sato, Koji, Daisuke Onodera, Mitsuhiro Hibino et Takeshi Yao. « Development of Bioactive Organic Polymer Coated with Ceramic Thin Films Synthesized from Aqueous Solution ». Key Engineering Materials 309-311 (mai 2006) : 771–74. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.771.

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Poly methyl methacrylate(PMMA) with mar resistant or poly ethtylene(PE) substrates were surface-treated by applying plasma discharge or alkaline solution. Ceramic thin film comprised of silicon oxide, titanium oxide and zirconium oxide was formed on these surface treated substrates respectively from an aqueous solution, and after the formation of ceramic thin film, titanium oxide thin film was also coated on them from aqueous solution at ordinary temperature and pressure. The thin film coated polymer material was tested in mechanical property. The thin film was hard and the adhesion strength to the organic polymer substrate was very high. The substrate was soaked in SBF and apatite was formed on the substrate. This method is promising for developing hard and soft tissue implants with various mechanical properties as well as high bioactivity.

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Hwang, Sung-Ho, Seong Hui Hong, Young Kwang Kim, Won Wook Jeong, Oh Kyung Kwon et Sang Kyoo Lim. « Preparation of hydrophobic fabric using cross-linked fluorinated poly methacryalte copolymer nanobeads ». Textile Research Journal 89, n^o 11 (15 août 2018) : 2057–66. http://dx.doi.org/10.1177/0040517518794346.

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In this study, we synthesized cross-linked poly methyl methacrylate beads and cross-linked fluorinated poly methacryalte copolymer (F-cPMMA) beads by the dispersion polymerization method with methyl methacrylate monomer, ethylene glycol dimethacrylate, and 2,2,2-trifuloroethyl methacrylate. The size of cross-linked PMMA and F-cPMMA beads was about 100 nm. Then we developed a new geometrical high-hydrophobic film by embedding the F-cPMMA nanobeads on polyurethane (PU) film. The PU film containing fluorinated poly methacryalte copolymer beads showed a greater hydrophobic property than the non-fluorinated one in the range of 1–10 wt.%. For the purpose of industrial application of the PU films, we applied 0.1–1 wt.% of beads on the fabric by the laminating method. The PU film containing 1 wt.% of fluorinated poly methacryalte copolymer beads, which was laminated onto nylon fabric, showed the best performance of hydrophobic property (water contact angle, 79°) and moisture vapor transmission rate (8797 g·m–2·24 h).

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Tan, KimHan, Lingenthiran Samylingam, Navid Aslfattahi, Mohd Rafie Johan et Rahman Saidur. « Investigation of improved optical and conductivity properties of poly(methyl methacrylate)–MXenes (PMMA–MXenes) nanocomposite thin films for optoelectronic applications ». Open Chemistry 20, n^o 1 (1 janvier 2022) : 1416–31. http://dx.doi.org/10.1515/chem-2022-0221.

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Abstract Polymer matrix composites composed of poly(methyl methacrylate) (PMMA) and MXenes (Ti3C2T x ) are synthesized using direct solution blending and casting techniques. MXenes are a new family of two-dimensional materials. Both optical and conductivity properties of the resulting PMMA-MXene nanocomposite thin films are studied as a function of MXene concentration, for the first time. The resulting thin films are in the micrometer range (8.10–8.80 µm) in thickness. As the concentration of MXenes increases, the PMMA embeds MXenes, causing structural disturbance but without any change in the crystal structure. The MXene thickness in single-layered structure is 15–20 nm. Optical investigations such as UV-Vis absorption, absorption coefficient, extinction coefficient, and band gap have been reported to study the light absorption of nanocomposites. Resistivity measurement associated with electrical conductivity is studied. The relationship between optical responses and electrical conductivity is discussed. When compared to pure PMMA (1 × 10−14 to 1 × 10−13 S m−1), nanocomposites have electrical conductivity that is more than 3,000 times higher. The nanocomposites containing 15 wt% MXenes had the highest conductivity of 1.35 × 10−3 S m−1. Both the conductivity improvement and tunable optical findings accelerate the route of integrating MXenes into polymers to create more promising multifunctional composites for optoelectronic applications such as conductive electrodes, thin film transistors, and logic circuits.

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Fleming, George, Jenny Aveyard, Joanne L. Fothergill, Fiona McBride, Rasmita Raval et Raechelle A. D’Sa. « Effect of Polymer Demixed Nanotopographies on Bacterial Adhesion and Biofilm Formation ». Polymers 11, n^o 12 (21 novembre 2019) : 1921. http://dx.doi.org/10.3390/polym11121921.

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As the current global threat of antimicrobial resistance (AMR) persists, developing alternatives to antibiotics that are less susceptible to resistance is becoming an urgent necessity. Recent advances in biomaterials have allowed for the development and fabrication of materials with discrete surface nanotopographies that can deter bacteria from adhering to their surface. Using binary polymer blends of polystyrene (PS), poly(methyl methacrylate) (PMMA) and polycaprolactone (PCL) and varying their relative concentrations, PS/PCL, PS/PMMA and PCL/PMMA polymer demixed thin films were developed with nanoisland, nanoribbon and nanopit topographies. In the PS/PCL system, PS segregates to the air-polymer interface, with the lower solubility PCL preferring the substrate-polymer interface. In the PS/PMMA and PCL/PMMA systems, PMMA prefers the air-polymer interface due to its greater solubility and lower surface energy. The anti-adhesion efficacy of the demixed films were tested against Pseudomonas aeruginosa (PA14). PS/PCL and PCL/PMMA demixed films showed a significant reduction in cell counts adhered on their surfaces compared to pure polymer control films, while no reduction was observed in the counts adhered on PS/PMMA demixed films. While the specific morphology did not affect the adhesion, a relationship between bacterial cell and topographical surface feature size was apparent. If the surface feature was smaller than the cell, then an anti-adhesion effect was observed; if the surface feature was larger than the cell, then the bacteria preferred to adhere.

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Malina, Ilze, et Valdis Kampars. « Comparison of Luminescent Properties in Solid-State and Polymer Films of Eu(III) Complexes Containing 2-Acylindandione Ligands ». Key Engineering Materials 762 (février 2018) : 239–43. http://dx.doi.org/10.4028/www.scientific.net/kem.762.239.

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The Europium(III) ternary complexes Eu(BID)3(PHEN) and Eu(MBID)3(PHEN) (BID – 2-benzoyl-1,3-indandione, MBID - 2-(4-methylbenzoyl)-1,3-indandione and PHEN – 1,10-Phenantroline) were synthesized, characterized and incorporated into poly methyl methacrylate (PMMA) and poly-N-vinylcarbazole (PVK) matrixes. Emission properties in solid-state and polymer films were investigated through excitation spectra, emission spectra and absolute photoluminescence quantum yields (PLQY). Both complexes in their solid-state and films exhibited red-light luminescence with narrow bands corresponding to Eu(III) ion emission. In solid-state complexes were characterized with PLQY of 6% and 10%, in PVK matrixes quantum yield dropped down to 4%, however, in PMMA films exhibited similar luminescence PLQY than in solid-state.

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Qazi, Raina Aman, Rozina Khattak, Luqman Ali Shah, Rizwan Ullah, Muhammad Sufaid Khan, Muhammad Sadiq, Mahmoud M. Hessien et Zeinhom M. El-Bahy. « Effect of MWCNTs Functionalization on Thermal, Electrical, and Ammonia-Sensing Properties of MWCNTs/PMMA and PHB/MWCNTs/PMMA Thin Films Nanocomposites ». Nanomaterials 11, n^o 10 (6 octobre 2021) : 2625. http://dx.doi.org/10.3390/nano11102625.

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Partially biodegradable polymer nanocomposites Poly(3-Hydroxybutyrate) (PHB)/MultiwalledCarbon Nanotubes (MWCNTs)/Poly(Methyl Methacrylate) (PMMA)and non-biodegradable nanocomposites (MWCNTs/PMMA) were synthesized, and their thermal, electrical, and ammonia-sensing properties were compared. MWCNTs were chemically modified to ensure effective dispersion in the polymeric matrix. Pristine MWCNTs (p-MWCNTs) were functionalized with –COOH (a-MWCNTs) and amine groups (f-MWCNTs). Then, PHB grafted multiwalled carbon nanotubes (g-MWNTs) were prepared by a ‘grafting to’ technique. The p-MWCNTs, a-MWCNTs, f-MWCNTs, and g-MWCNTs were incorporated into the PMMA matrix and PMMA/PHB blend system by solution mixing. The PHB/f-MWCNTs/PMMA blend system showed good thermal properties among all synthesized nanocomposites. Results from TGA and dTGA analysis for PHB/f-MWCNTs/PMMA showed delay in T5 (about 127 °C), T50 (up to 126 °C), and Tmax (up to 65 °C) as compared to neat PMMA. Higher values of frequency capacitance were observed in nanocomposites containing f-MWCNTs and g-MWCNTs as compared to nanocomposites containing p-MWCNTs and a-MWCNTs. This may be attributed to their excellent interaction and good dispersion in the polymeric blend. Analysis of ammonia gas-sensing data showed that PHB/g-MWCNTs/PMMA nanocomposites exhibited good sensitivity (≈100%) and excellent repeatability with a constant response. The calculated limit of detection (LOD) is 0.129 ppm for PHB/g-MWCNTs/PMMA, while that of all other nanocomposites is above 40 ppm.

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Khun, Nay Win, Poh Yueh Loong, Erjia Liu et Lin Li. « Enhancing electrical and tribological properties of poly(methyl methacrylate) matrix nanocomposite films by co-incorporation of multiwalled carbon nanotubes and silicon dioxide microparticles ». Journal of Polymer Engineering 36, n^o 1 (1 janvier 2016) : 23–30. http://dx.doi.org/10.1515/polyeng-2014-0346.

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Abstract Multiwalled carbon nanotubes (MWCNTs) and silicon dioxide microparticles (SiO2-MPs) were co-incorporated in poly(methyl methacrylate) (PMMA) matrices to form PMMA/MWCNT-SiO2-MP nanocomposite films. The SiO2-MP content in the nanocomposite films was varied at a fixed MWCNT content of 4 wt% to investigate the effect of SiO2-MP content on the electrical and tribological properties of the PMMA/MWCNT-SiO2-MP nanocomposite films. The co-incorporation of MWCNTs and SiO2-MPs dramatically lowered the electrical resistance of the nanocomposite films compared to that of the PMMA film, while higher fractions of SiO2-MPs more effectively promoted the decrease in the electrical resistance of the nanocomposite films by improving the conductive networks formed by the MWCNTs in the PMMA matrices. Although the friction of the nanocomposite films significantly increased with increased SiO2-MP content due to the promoted mechanical interlocking between the surface asperities of two mating surfaces, the wear of the nanocomposite films was much less severe than that of the PMMA film during ball-on-disc tribological tests.

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Maxim, Askar A., Shynggys N. Sadyk, Damir Aidarkhanov, Charles Surya, Annie Ng, Yoon-Hwae Hwang, Timur Sh Atabaev et Askhat N. Jumabekov. « PMMA Thin Film with Embedded Carbon Quantum Dots for Post-Fabrication Improvement of Light Harvesting in Perovskite Solar Cells ». Nanomaterials 10, n^o 2 (9 février 2020) : 291. http://dx.doi.org/10.3390/nano10020291.

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Perovskite solar cells (PSCs) with a standard sandwich structure suffer from optical transmission losses due to the substrate and its active layers. Developing strategies for compensating for the losses in light harvesting is of significant importance to achieving a further enhancement in device efficiencies. In this work, the down-conversion effect of carbon quantum dots (CQDs) was employed to convert the UV fraction of the incident light into visible light. For this, thin films of poly(methyl methacrylate) with embedded carbon quantum dots (CQD@PMMA) were deposited on the illumination side of PSCs. Analysis of the device performances before and after application of CQD@PMMA photoactive functional film on PSCs revealed that the devices with the coating showed an improved photocurrent and fill factor, resulting in higher device efficiency.

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Lyly Nyl, Ismail, Zulkefle Habibah, Herman Sukreen Hana et Mohamad Rusop. « Influence of Different Types of Silanes on the Properties of Nanocomposite PMMA : TiO₂ Thin Films ». Advanced Materials Research 667 (mars 2013) : 255–59. http://dx.doi.org/10.4028/www.scientific.net/amr.667.255.

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This paper reported the effect of silane on the electrical properties of the nanocomposite poly(methyl methacrylate): titanium dioxide (PMMA:TiO2) films. Different types of silane were added directly into the nanocomposite PMMA:TiO2 solution. Electrical properties result shows that when different silane were use in the nanocomposite solution give different electrical properties. Sample 1 (without silane) and 4 (trimethoxymethylsilane) shows the highest resistivity and lowest leakage current density. Meanwhile sample 3 (triethoxyvinylsilane) indicate that are not a suitable silane to be added into the nanocomposite PMMA:TiO2 solution because it produce poor insulator behavior.

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Gupta, A., K. Malik et R. Kumar. « Optical constants of the as-prepared and annealed (Se80Te20)94Ag6/PMMA thin films ». Chalcogenide Letters 18, n^o 9 (septembre 2021) : 549–56. http://dx.doi.org/10.15251/cl.2021.189.549.

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Thin films of (Se80Te20)94Ag6/PMMA have been deposited on glass substrate by thermal co-evaporation technique. Melt quenching approach has been adopted to prepared bulk (Se80Te20)94Ag6 chalcogenide glass. Glass transition temperature of bulk (Se80Te20)94Ag6 glass and poly (methyl methacrylate) (PMMA) polymer have been found out by differential scanning calorimetry (DSC) at a heating rate of 10 K/min. Thin films were annealed above glass transition temperatures of glass (332 K) and polymer (340 K) at two different temperatures 343 K and 365 K. The presence of different phases in annealed film was confirmed by X-ray diffraction studies. Transmission spectra of as-deposited and annealed films were obtained by Uv-Vis spectroscopy in the wavelength range of 350-900 nm. To analyze refractive index dispersion Wemple-Didomenico model have been used. Optical parameters viz refractive index (n), extinction coefficient (k), real and imaginary dielectric constants (ε′ and ε′′) and optical band gap (Eg) are calculated by using optical transmittance. The increasing behavior of the optical band gap with increase in annealing temperature is explained on the basis of density of state model.

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