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Optical linearity and bandgap analysis of RhB-doped PMMA/FTO polymeric composites films: A new designed optical system for laser power attenuation
摘要： Thin films of PMMA doped with Rhodamine B-dye have deposited successfully on a fluorine-doped tin oxide (FTO) glass substrate as a new optical system by using a spin coating method. This new system is promising to be used in various technological applications as solar energy cells, electronic apparatuses, devices of optical filter properties and optoelectronic tools. X-ray diffraction (XRD) illustrates a uniform and semicrystalline structure in nature for the obtained thin films. A spectrophotometric investigation was applied on the prepared thin films at the range of (300–2500 nm) for the wavelength. Both linear refractive index and absorption index values were measured to be reduced as the wavelength was raised. Tauc’s plot indicated that direct and indirect transitions were displayed by the thin film. Both direct and indirect bandgaps were calculated and analyzed. Continuous waves of the green laser beam (operating at 532), and He-Ne laser beam (operating at 632.8 nm) were used to study the optical properties of the prepared thin films with different dye concentrations. The results illustrated that the polymeric composites films are highly attenuated for the laser beam of 532 nm. The designed RhB-doped PMMA/FTO composites can be extensively appropriate to the optoelectronic applications.
关键词： Laser power attenuations,Polymeric composite films,Direct and indirect bandgap,Rhodamine B dye,PMMA/FTO films
更新于2025-09-11 14:15:04
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Optical and Structural Characteristics of CdSe/PMMA Nanocomposites
摘要： Nanocomposites of polymethylmethacrylate (PMMA) and CdSe were fabricated by a casting technique. The result showed that CdSe@PMMA can be used in white and green light emitting devices. 0.01CdSe@PMMA exhibits monochromatic green color emission with the highest fluorescent quantum yield and lowest optical band gap value, while CdSe@PMMA with other ratios shows a multicolor emission. The band-edge emits in the vicinity of 280 – 296 nm but a more stable intensive green color emission at 553 nm is found for 0.01CdSe@PMMA. The change in Eg (4.18 to 4.4) eV values is due to the interaction between the PMMA polymer and CdSe.
关键词： nanocomposites,optical properties,PMMA,light emitting devices,CdSe
更新于2025-09-10 09:29:36
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A Late Complication of Polymethyl Methacrylate(PMMA) Intraocular Lens- an Unusual Degeneration
摘要： Polymethyl methacrylate (PMMA) was the material used in Sir Harold Ridley’s original intraocular lens (IOL). Until the last decade, PMMA has enjoyed a reputation as a reliable and high quality optical material with very few complications associated with PMMA material alterations having been reported. Here, we report a clinical case of a 72 year old gentleman who presented with progressively increasing glare and decreased vision 20 years after his routine PMMA IOL implantation. The lens was explanted and sent for pathological analysis which revealed grey-brown ‘bubble-like’ lesions which were empty. Scanning electron microscopy showed cracks in the PMMA material which were correlated to decreased optical quality. The current findings are dissimilar from the known phenomenon of ‘snow flake degeneration’, which was the only reported late complication of PMMA lenses. This case report describes a new variant of an unexpected late complication associated with PMMA lenses.
关键词： PMMA,Complication,IOL,Degeneration
更新于2025-09-10 09:29:36
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Optical and Electrical Characterization of Pure PMMA for Terahertz Wide-band Metamaterial Absorbers
摘要： The characteristics of relative permittivity and reflectance for poly (methyl methacrylate) (PMMA) films prepared by spin-coating were investigated and an excellent wideband terahertz (THz) metamaterial absorber (MA) had been fabricated by employing PMMA film as the dielectric layer. XRD and AFM indicated that all the PMMA films with thicknesses from 11 to 17 μm were amorphous and extremely smooth with roughness about 0.203 nm. Raman results demonstrated that vibration strength of the same covalent bonds tends to be consistent with an increase in film thickness. The dual beam laser interferometer (DBLI) was employed to study the influence of applied frequency and thickness on the relative permittivity, and the results exhibited dielectric constants increased from 2.88 to 4.04 with the thickness increasing from 9 to 14 μm. And the dielectric constants for PMMA films with a certain thickness (8 μm) gradually declined when the applied frequency increased from 100 to 105 Hz; besides, the dielectric constant in THz band was forecasted approximately 2.5. The terahertz time domain spectrometer (THz-TDS) results revealed that the THz reflectance was of gradual degradation from 80 to 58% at 3.2 THz, as the thickness increased from 11 to 17 μm. In addition, the UV-VIS spectrum showed that thickness had little effect on reflectance and transmittance in visible region, leading to the almost same Eg (energy gap) about 3.7 eV. At last, by employing PMMA film as the dielectric layer, a highly wideband metamaterial absorber with absorption > 80% from 4.1 to 7.4 THz was fabricated.
关键词： Terahertz,Metamaterial absorber,PMMA,Reflectance,Permittivity
更新于2025-09-10 09:29:36
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Love Wave Sensor Based on PMMA/ZnO/Glass Structure for Liquids Sensing
摘要： PMMA/ZnO/glass structure was investigated to enhance Love mode sensor sentivities. The phase velocities and the attenuation of the acoustic wave propagating along the PMMA/30° tilted c-axis ZnO/glass structure contacting a viscous non-conductive liquid were calculated for different PMMA (Polymethyl methacrylate) and ZnO guiding layer thicknesses, added mass thicknesses, and liquid viscosity and density. The sensor velocity and attenuation sensitivities were also calculated for different environmental parameters. The resulted sensitivities to liquid viscosity and added mass were optimized by adjusting the ZnO and PMMA guiding layer thickness corresponding to a sensitivity peak. The present analysis is of importance in manufacturing and applications of the PMMA-ZnO-glass structure Love wave sensors for the detection of liquids properties, such as viscosity, density and mass anchored to the sensor surface.
关键词： surface acoustic waves,PMMA,love wave sensor,ZnO
更新于2025-09-09 09:28:46
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Preparation and Performance of Porous Polymer Electrolytes Doped with Nano-Al <sub/>2</sub> O <sub/>3</sub>
摘要： Porous polymer electrolytes (PPEs) doped with nano-Al2O3 were prepared by a joint application of ultrasonic treatment and control evaporation in vacuum oven. The morphology, pore size distribution, thermal, electrochemical and mechanical properties of the PPEs were investigated. The porosity distribution of PPEs was uniform and their pore size was relatively modest. The total resistance (R t) of PPEs with 10% Al2O3 is only 9 Ω at 80 °C. The maximum tensile strength of the PPEs membranes reached to 24.43 MPa. The results show that nano-Al2O3 can improve the comprehensive performance of PPEs without compromising their conductivity and diplayed the good application prospects of Al2O3-modi?ed PPEs for lithium-ion batteries.
关键词： PEO-PMMA Blends,Nano-Al2O3,Porous Polymer Electrolytes,Interfacial Compatibility,Lithium-Ion Batteries
更新于2025-09-09 09:28:46
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A novel approach to prepare one-pot Fe/PPy nanocomposite and evaluation of its microwave, magnetic, and optical performance
摘要： The aim of this study was preparation of Fe/Fe2O3/Fe3O4 (Fe)/polypyrrole (PPy) nanocomposite using reductive method and investigation of its microwave absorbing properties using polymethylmethacrylate (PMMA) medium. Firstly, PPy was prepared by an oxidative polymerization method with Fe3+ as a doping agent. Next, the Fe/PPy nanocomposite was formed by insitu reduction of Fe2+ and remained Fe3+ with sodium borohydride solution under an inert nitrogen atmosphere. Finally, PPy and Fe/PPy nanostructures were separately suspended within the PMMA matrix to examine their microwave absorbing characteristics. The prepared PPy and Fe/PPy nanostructures were studied using the Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The diffuse reflection spectroscopy (DRS) analysis presented a 1.79 eV band gap for the Fe/PPy nanocomposite based on the Kubelka–Munk theory. The vibrating sample magnetometer (VSM) revealed that magnetic properties were reinforced in the Fe/PPy nanocomposite. According to the results obtained by vector network analyzer (VNA), the maximum reflection loss of Fe/PPy/PMMA nanocomposite was -76.02 dB at 8.96 GHz with a thickness of 3.2 mm, absorbing all of the x-band frequency more than 12.72 dB with a thickness of 2.8 mm. Interestingly, the Fe/PPy/PMMA nanocomposite demonstrated a bandwidth > 3.4 GHz more than 10 dB from 2.2 to 3.2 mm at the x-band frequency.
关键词： Optical performance,Magnetic properties,Fe/PPy/PMMA,Microwave absorption
更新于2025-09-09 09:28:46
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Kinetic Study of Degrafting Poly(methyl methacrylate) Brushes from Flat Substrates by Tetrabutylammonium Fluoride
摘要： Polymer degrafting is a process in which surface-attached polymer brushes are removed from the substrate by breaking a chemical bond in proximity to the substrate. This paper provides insight into the kinetics of degrafting poly(methyl methacrylate) (PMMA) brushes using tetrabutylammonium fluoride (TBAF) and demonstrates how the process can be modeled using a series of degrafting reactions. The trichlorosilane-based polymerization initiator utilized here to synthesize PMMA grafts by surface-initiated atom transfer radical polymerization anchors to the silica substrate by up to three potential attachment points. During the degrafting sequence this anchoring reduces to two and one chemical bond and finally results in complete liberation of the PMMA macromolecule from the substrate. We investigate the effect of TBAF concentration, the initial grafting density of PMMA grafts on the substrate, and TBAF exposure time on degrafting of PMMA by monitoring the instantaneous areal grafting density of PMMA on the substrate.
关键词： PMMA brushes,Polymer degrafting,TBAF,kinetics,surface-initiated atom transfer radical polymerization
更新于2025-09-04 15:30:14
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Direct formation of gold nanorods on surfaces using polymer-immobilised gold seeds
摘要： Herein, we present the formation of gold nanorods (GNRs) on novel gold–poly(methyl methacrylate) (Au–PMMA) nanocomposite substrates with unprecedented growth control through the polymer molecular weight (Mw) and gold-salt-to-polymer weight ratio. For the first time, GNRs have been produced by seed-mediated direct growth on surfaces that were pre-coated with polymer-immobilised gold seeds. A Au–PMMA nanocomposite formed by UV photoreduction has been used as the gold seed. The influence of polymer Mw and gold concentration on the formation of GNRs has been investigated and discussed. The polymer nanocomposite formed with a lower Mw PMMA and 20 wt % gold salt provides a suitable medium for growing well-dispersed GNRs. In this sample, the average dimension of produced GNRs is 200 nm in length with aspect ratios up to 10 and a distribution of GNRs to nanoparticles of nearly 22%. Suitable characterization techniques such as AFM and SEM have been used to support concept of the proposed growth method.
关键词： direct surface growth,gold nanorods,nanocomposites,atomic force microscopy (AFM),poly(methyl methacrylate) (PMMA)
更新于2025-09-04 15:30:14
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Up-conversion luminescence of RE3+ -doped polymer composites KGd(WO4)2&PMMA
摘要： Poly(methyl methacrylate) (PMMA)-based luminescent materials are of prime interest for many new optoelectronic devices. This work presents the spectroscopic properties of PMMA-based composites containing KGd(WO4)2:Yb3+/Er3+/Tm3+, KGd(WO4)2:Yb3+/Tm3+ and KGd(WO4)2:Yb3+/Er3+ powders. These systems exhibit effective multicolor up-conversion luminescence in VIS and NIR spectral range under 980 nm excitation. The vibrational properties of the composites were investigated for the first time using the μ-Raman spectroscopy. The obtained results suggest that the KGd(WO4)2:Yb3+/Er3+/Tm3+&PMMA integrated system can be successfully used as a new phosphor for the up-conversion based optoelectronic devices.
关键词： Micro-crystals,Rare earth ions,PMMA,KGd(WO4)2,Composites,Up-conversion
更新于2025-09-04 15:30:14