Poly Methyl Methacrylate Substrates Research Articles

FAT-GEMs: (field assisted) transparent gaseous-electroluminescence multipliers

The idea of implementing electroluminescence-based amplification through transparent multi-hole structures (FAT-GEMs) has been entertained for some time. Arguably, for such a technology to be attractive it should perform at least at a level comparable to conventional alternatives based on wires or meshes. We present now a detailed calorimetric study carried out for 5.9 keV X-rays in xenon, for pressures ranging from 2 to 10 bar, resorting to different geometries, production and post-processing techniques. At a reference voltage 5 times above the electroluminescence threshold (EEL,th ∼ 0.7 kV/cm/bar), the number of photoelectrons measured for the best structure was found to be just 18% below that obtained for a double-mesh with the same thickness and at the same distance. The energy resolution stayed within 10% (relative) of the double-mesh value. An innovative characteristic of the structure is that vacuum ultraviolet (VUV) transparency of the polymethyl methacrylate (PMMA) substrate was achieved, effectively, through tetraphenylbutadiene (TPB) coating of the electroluminescence channels combined with indium tin oxide (ITO) coating of the electrodes. This resulted in a × 2.25-increased optical yield (compared to the bare structure), that was found to be in good agreement with simulations if assuming a TPB wavelength-shifting-efficiency at the level of WLSE=0.74–1.28, compatible with expected values. This result, combined with the stability demonstrated for the TPB coating under electric field (over 20 h of continuous operation), shows great potential to revolutionize electroluminescence-based instrumentation.

Design optimization for microstrip antennas based on polymethyl methacrylate (PMMA) substrate and carbon nanotube (CNT) conductive material in sub-6 Ghz band

Abstract Background The rapid expansion of modern smart applications, demanding faster data transfer and extensive bandwidth, has prompted the development of new-generation networks like 5G and 6G. These networks encompass additional frequency bands such as sub-6 GHz, millimeter waves, and terahertz bands to meet the growing bandwidth requirements. However, despite the substantial bandwidth available in these bands, several challenges must be addressed to overcome unfavorable propagation characteristics. Moreover, numerous applications necessitate wireless devices with antennas that exhibit high flexibility and exceptional radiation responses, particularly when subjected to bending effects. This requirement highlights the importance of polymers-based antennas that can adapt to changing conditions while maintaining optimal performance. The present comprehensive study delves into the performance evaluation of rectangular and circular microstrip antennas utilizing PMMA (polymethyl methacrylate) polymer substrate with varying thicknesses. Results Notably, CNTs (Carbon Nanotubes) are employed as an alternative to traditional copper for the conductive part and ground plane. Both PMMA-based antennas, integrated with CNTs, exhibit a compact footprint of 27.8 × 47.8 × 1.5 mm3 for the circular antenna and 22.8 × 39.5 × 1.5 mm3 for the rectangular antenna. Impressively, the realized gain of both antennas surpasses 5 dBi, demonstrating robust performance in both flat and bending scenarios across different substrate thicknesses. Conclusions The rectangular antenna achieves a bandwidth of approximately 200 MHz, while the circular microstrip antenna showcase annotable bandwidth of 500 MHz. These exceptional outcomes position the two microstrip antennas as highly suitable for a diverse range of emerging applications within the sub-6 GHz band (the frequency range below 6 GHz in the radio spectrum). Thus, the combination of PMMA substrate, CNTs and the compact form factor of the antennas presents a compelling solution for meeting the demands of modern applications requiring efficient wireless communication with enhanced performance and bandwidth.

One-step fabricating a PDMS optical lens based on surface charging and edge pining effects of a PDMS droplet

This paper presents a one-step method for fabricating a PDMS optical lens based on the surface charging and edge pining effects of a PDMS droplet. This method works by electrically lifting the air-liquid PDMS interface initially stabilized by the edge pining effect of a PDMS droplet on a polymethyl methacrylate (PMMA) substrate. The electrical lifting was achieved under the force interaction between the negative surface charges of the PDMS droplet and the non-uniform electric field generated by a needle-plate electrode pair. Experimental results show that the electrical lifting was achieved in about 10 seconds. With the increase of the applied electric field, the magnification of the fabricated lens increases. Fabricating a lens with a resolution of 32 lp/mm and a magnification of 23.92 times was obtained under an averaged electric field of 12500 V/cm. Chlorophyll-fluorescence-based living algae detection with the PDMS lens and a smartphone imaging system was successfully achieved.

Tunable formation of gold nanoparticles on polymer by keV ion beam irradiation

The formation of nanostructures from a thin Au film deposited on a polystyrene and polymethylmethacrylate substrate under keV monatomic P, Ta and molecular PF4 ion irradiation is studied. The formation of nanoparticles on both kinds of polymers is shown. Heavy Ta ions are most effective in altering the Au layer, whereas its transformation by light P or molecular PF4 ions is less pronounced. Irradiation with PF4 ions has a much smaller effect on the PS and PMMA substrate bulk compared to that with monatomic P ions. The crucial role of collision cascade density in the process of thin metallic film coagulation on polymer substrate is revealed. During ion bombardment, transmitted IR light intensity increases proportionally to the area covered by the metal film, which makes it possible to use FTIR as a rapid technique to estimate the state of the nanoparticle formation process.

Low-cost inertial microfluidic device for microparticle separation: A laser-Ablated PMMA lab-on-a-chip approach without a cleanroom

Although microparticles are frequently used in chemistry and biology, their effectiveness largely depends on the homogeneity of their particle size distribution. Microfluidic devices to separate and purify particles based on their size have been developed, but many require expensive cleanroom manufacturing processes. A cost-effective, passive microfluidic separator is presented, capable of efficiently sorting and purifying particles spanning the size range of 15 µm to 40 µm. Fabricated from Polymethyl Methacrylate (PMMA) substrates using laser ablation, this device circumvents the need for cleanroom facilities. Prior to fabrication, rigorous optimization of the device's design was carried out through computational simulations conducted in COMSOL Multiphysics. To gauge its performance, chitosan microparticles were employed as a test case. The results were notably promising, achieving a precision of 96.14 %. This quantitative metric underscores the device's precision and effectiveness in size-based particle separation.This low-cost and accessible microfluidic separator offers a pragmatic solution for laboratories and researchers seeking precise control over particle sizes, without the constraints of expensive manufacturing environments. This innovation not only mitigates the limitations tied to traditional cleanroom-based fabrication but also widens the horizons for various applications within the realms of chemistry and biology.

Polyfluorinated Naphthalene-bis-hydrazimide for Solution-Grown n-Type Semiconducting Films.

Naphthalene tetracarboxylic diimides (NDIs), possessing low-lying and tunable LUMO levels, are of wide interest for their aptitude to provide cost-effective, flexible, and environmentally stable n-type organic semiconductors through simple solution processing. NDI-based aromatic hydrazidimides are herein studied in relation to their chemical and environmental stability and as spin-coated stable thin films. In the case of the pentafluorinated residue, these were found to be crystalline, highly oriented, and molecularly flat (roughness = 0.3 nm), based on optical and atomic force microscopy, X-ray diffraction in specular and grazing incidence geometry, and X-ray reflectivity measurements. A new polymorph, previously undetected during the isolation of bulk powders or in their controlled thermal treatments, is found in the thin film and was metrically and structurally characterized from 2D GIWAXS patterns (monoclinic, P2/c, a = 17.50; b = 4.56; c = 14.24 Å; β = 84.8°). This new thin-film phase, TF-F5, is formed no matter whether silicon, glass, or polymethylmethacrylate substrates are used, thus opening the way to the preparation of solution-grown flexible semiconducting films. The TF-F5 films exhibit a systematic and rigorous molecular alignment with both orientation and packing favorable to electron mobility (μ = 0.02 cm2 V-1 s-1). Structural and morphological differences are deemed responsible for the absence of measurable conductivity in thin films of polyfluorinated analogues bearing -CF3 residues on the hydrazidimide aromatic rings.

Enhancing circular microstrip antenna performance with polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA) substrates in sub-6 GHz: a comparative study

Enhancing circular microstrip antenna performance with polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA) substrates in sub-6 GHz: a comparative study

CO2 laser micromachining on PMMA

Laser micromachining is one of the widely accepted micromachining methods to create microchannels for various applications. One of the major challenges is laser micromachining is to create microchannels with high surface quality. In the present work, the microchannels generated during the CO2 laser micromachining of polymethylmethacrylate substrate are investigated. The laser parameters such as power, machining speed and number of passes were varied to create the micro channels. The nature of surface generated was investigated. The findings will also help attain the optimum process parameters for the laser micromachining of polymethyl-methacrylate.

Mechanistic Insights into Synaptic Plasticity Behaviors of Electrolyte-Gated Flexible Transistor Devices.

Biological synaptic function simulation using flexible electronic devices based on low-dimensional semiconductor materials is an emerging and rapidly evolving research field with promising applications in brain-like computers and artificial intelligence systems. In this work, we present the fabrication of solution compatible MoS2 thin-film transistors on the ultrathin polymethyl methacrylate substrates via layer-by-layer assembly followed by a one-step transfer printing method. The MoS2 transport channel is controlled by ionic liquid gating with 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, resulting in excellent synaptic performances for emulating memory and perception synapse functions. To investigate the synaptic behaviors, we conduct a series of synaptic spike-dependent experiments and propose an advanced model that delineates the long-term plasticity and short-term plasticity with separate characteristic factors. These findings provide insights into the fundamental mechanisms of synaptic plasticity in electric double-layer devices and contribute to a better understanding of their synaptic performances. In addition, we examine the effects of bending conditions on synaptic plasticity and synaptic weights, unveiling the synergistic interplay between mechanical deformation and synaptic behaviors. Our experimental results, combined with the developed model, are in good agreement and shed light on the influence of mechanical flexibility on the synaptic properties of the devices. In summary, this study establishes a solid foundation for further development of flexible synaptic devices from both practical and theoretical perspectives.

Bonding of thermoplastic microfluidic device by water assistance

We present a water-assisted microwave bonding (H2O-μWave bonding) process for sealing thermoplastic microfluidic devices. We use water as the bonding reagent to assist the formation of covalent bonds after surface activation and water evaporation procedures. In surface activation step, we exam UV/Ozone and O2 plasma surface treatments and their effects of the surface wettability, optical transmissivity, surface morphology, and surface chemistry on a polymethyl methacrylate (PMMA) substrate in H2O-μWave bonding. After surface activation, water evaporation step was performed to form the bonds. The bonding can be simply formed by leaving the surface-activated pair in the room environment after water application. We examined the bonding strength and coverage of PMMA by both room temperature drying and microwave annealing approaches in H2O-μWave bonding. Finally, stability and multilayer bonding were also tested to evaluate the quality of H2O-μWave bonding.

Impact of noise on spinodal dewetting of liquid-liquid films

Spinodal dewetting provides fundamental insights into the physics at interfaces, such as van der Waals forces driving dewetting, dissipation processes or thermal fluctuations. The dewetting process of liquid bilayer systems still raises open problems involving two coupled moving interfaces. Comparison of experimental results of spinodally dewetting liquid polystyrene films from liquid polymethylmethacrylate substrates, with predictions from linear stability analysis, we demonstrate that both the spinodal wavelength and the rupture times show significant differences. Key for this discrepancy is the altered mode selection process due to the initial surface roughness of the liquid-air and liquid-liquid interfaces, which is perturbed by partially correlated colored noise in the linearly unstable region. The strong effect of noise on mode selection and rupture time is confirmed by comparing experimental results with numerical solutions of the full dynamic nonlinear model and suggest new strategies to include thermal fluctuations into modeling these processes.

Synthesis, structural, photocatalytic, wettability and optical properties of TiO2 films on polymethyl methacrylate substrates

TiO2 thin films on polymethyl methacrylate (PMMA) substrates were prepared on Al foils using reactive dc magnetron sputtering followed by transformation to the PMMA substrates via chemical method. The films were prepared at different temperature preparation routes of 100, 150 and 200 °C. XRD revealed the formation amorphous structure for films prepared at 150 °C and mixed anatase/rutile crystalline phases with rutile domination at higher-temperature preparation route of 150 and 200 °C. Amorphous or homogeneous and uniform nanoparticles morphologies with particle sizes depended on the temperature preparation route were obtained for the TiO2 films. The optical properties are affected strongly by the temperature preparation route. The optical band gap values increased from 3.05 eV to 3.47 eV with increasing the temperature preparation route from 100 °C to then to 200 °C, respectively. The higher refractive index and the lower extinction coefficient were obtained for the films prepared at 200 °C. The methylene blue underwent effective photodegradation and the hydrophilicity initiated upon UV illumination. The TiO2 film prepared at 200 °C has the highest decomposition efficiency for methylene blue and the lowest water contact angle.

Structure–Property Relationships in Epoxyurethane Polymers Based on Erythritol Dicarbonate

AbstractThe highly reactive erythritol dicarbonate (EDC) allows facile design and preparation of solvent‐ and catalyst‐free epoxyurethane polymers. Diglycidyl ether of bisphenol‐A (DGEBA) and oligo polyhydroxyurethanes are used to produce epoxyurethane polymers (o‐PHUs). The o‐PHUs are prepared using cyclic carbonates derived from erythritol and various diamines (aliphatic amine and polyether amine) or polyamines (diethylene triamine (DETA) and triethylne tetramine (TETA)). Active secondary amino groups derived from o‐PHUs polyamines form hydrogen bonds between urethane carbonyls in epoxy hybrid networks with the highest cross‐linking density (1293 mol m−3), glass transition temperature Tg (93 °C), and ultimate tensile strength (34 MPa). And the ether bond provides a significant potential for hydrogen bonding between hydroxyl group and ether oxygen, forming strong hydrogen bond cross‐linking between molecular chains, with cross‐linking density and ultimate tensile strength comparable to polyepoxyurethane derived from polyamines, except for a lower Tg (27 °C). In addition, these polyepoxyurethanes have superior adhesion to wood, aluminum alloy, and polymethyl methacrylate (PMMA) substrates. This versatile oligo PHUs would provide a wide range of fabrication options for adhesive epoxyurethane polymers.

Experimental investigation of particle–droplet–substrate interaction

The impact of droplets on non-fixed spherical particles placed on a plane polymethyl methacrylate (PMMA) substrate is investigated. This interaction is a highly abstracted level of a high-pressure spray cleaning process. Water droplets in a diameter range between 0.68 and 1.66,{mathrm{mm}} and spherical particles (PMMA) with a diameter of 1.55 mm are used. The droplet velocity range of 1.05 le v_{mathrm{d}} le 2.0,{mathrm{m/s}} results in a Weber number range of 13,le ,{mathrm{We}},le ,94. The particle-droplet-substrate interactions are investigated for different Weber numbers, droplet-to-particle diameter ratios and eccentricities. Different droplet impact scenarios are identified: A—Lift-off during initial recoil; B—Lift-off during a later recoil; C—No Lift-off, deposition of the droplet and D—No Lift-off, wetting of the substrate. The behavior of the particle-droplet-substrate interaction is determined depending on Weber number and particle-to-droplet diameter. Additionally, the analysis of the eccentricity in relation to the lift-off behavior shows that the lift-off height and duration increases with the centrality. The investigation of temporal change of the half-spread and contact angle results in a criterion for the point in time at which the lift-off takes place. Finally, a simplified analytical model is provided quantifying the probability of the lift-off of the particle-droplet system after the interaction. Experimental and analytical results are used to create a map of occurring impact regimes in terms of the particle-droplet configuration.

A Simple and Effective Method to Adjust the Structure and Performance of DLC Films on Polymethyl Methacrylate(PMMA) Substrate

DLC (diamond-like carbon) films were prepared on Ti/PMMA(polymethyl methacrylate) under the different bias; the principal purpose of this study is to explore structural differences of films on Ti/PMMA with and without conductive material, and to further clarify the role of the conductive Ti interlayer in influencing the deposition mechanism. The results indicate that the films deposited on Ti/PMMA with conductive material exhibit uniform DLC structure and mechanical hardness when the bias voltage is ≥550 V. Furthermore, the deposited DLC does not change the wettability of PMMA, while the addition of the Ti interlayer virtually increases the risk of peeling off of the film. The results of the tribological study demonstrate the films on Ti/PMMA with conductive material have better tribological properties than those without conductive adhesive. This research work can provide basic theoretical guidance for depositing uniform DLC films on PMMA and even on all non-conductive substrates.

Laser crystallization of amorphous TiO2 on polymer

The deposition of crystalline TiO2 on polymers can boost its use in a large plethora of applications. In this work, we deposited, through the low-temperature atomic layer deposition (LT-ALD) technique, a thin layer of amorphous TiO2 on polymethyl-methacrylate (PMMA), and afterwards, we induced a phase transition from amorphous to crystalline anatase by pulsed UV-laser irradiation. A pulsed UV laser with a low penetration length was used to avoid the heating and damaging of the polymeric substrate. The diffusion of the heat and the temperature behaviour were simulated and discussed. We studied experimentally the effect of the laser fluence and pulse number on the amorphous-crystal transition. We observed the presence of two thresholds for the formation of the crystalline phase: on the fluence and the number of laser shots. Moreover, widening of pre-existing cracks is observed, as soon as fluence and the number of pulses increase. To improve further the quality of the deposited layer, we introduced a ZnO interlayer between TiO2 and the PMMA substrate. The effect of this interlayer was also discussed. Lastly, wettability, as a measure of the overall quality of the layer, was measured and interpreted by using the Cassie model.

Photocatalytic Activity of TiO2 Coatings Obtained at Room Temperature on a Polymethyl Methacrylate Substrate.

Titanium dioxide (TiO2) coatings have a wide range of applications. Anatase exhibits hydrophilic, antimicrobial, and photocatalytic properties for the degradation of organic pollutants or water splitting. The main challenge is to obtain durable anatase nanoparticle coatings on plastic substrates by using straightforward approaches. In the present study, we revealed the preparation of a transparent TiO2 coating on polymethylmethacrylate (PMMA), widely used for organic optical fibres as well as other polymer substrates such as polypropylene (PP), polystyrene (PS), and polycarbonate (PC). The films were spin-coated at room temperature without annealing; therefore, our approach can be used for thermo-sensitive substrates. The deposition was successful due to the use of stripped ultra-small (<4 nm) TiO2 particles. Coatings were studied for the photocatalytic degradation of organic pollutants such as MB, methyl orange (MO), and rhodamine B (RB) under UV light. The TiO2 coating on PMMA degraded over 80% of RB in 300 min under a 365 nm, 100 W mercury lamp, showing a degradation rate constant of 6 × 10−3 min−1. The coatings were stable and showed no significant decrease in degradation activity even after five cycles.

Structural, surface, optical, and antimicrobial characterization of I2/Polymethyl methacrylate and CuS/I2/polymethyl methacrylate thin films

In this study, I2/PMMA and CuS/I2/PMMA thin films were produced by Chemical Bath Deposition (CBD) on polymethyl methacrylate (PMMA) substrates, and their physicochemical and antimicrobial properties were analyzed. The film's surface tensions were characterized by KSV instruments, and the surface tensions for plain PMMA, I2/PMMA, and CuS/I2/PMMA thin films were 30.27, 28.77, and 31.86 mN/m, respectively. The I2 and CuS/I2 structures in the XRD patterns are amorphous. After coating CuS, the long rod-like extension structures are formed; spherical shapes form some agglomeration in some regions to SEM images. Chemical analysis was performed with an EDX spectrometer attached to SEM. The thicknesses and surface roughnesses of I2/PMMA and CuS/I2/PMMA thin films were determined to be 50.34 nm, 1126 nm; 62.03 nm and 204.99 nm via AFM, respectively. The optical spectra of the films were recorded in the range of 300–1100 nm with a UV-VIS spectrophotometer. The antibacterial and antifungal properties of I2 and CuS coating were evaluated against facultative gram-negative E. Coli and C. Albicans. The coated films exhibited excellent antimicrobial performance.

Bacillus subtilis‐based microbial enhanced oil recovery (MEOR) in polymer microfluidic chip

AbstractMicrobial enhanced oil recovery (MEOR) is a tertiary oil recovery process that manipulates the microbial environment inside oil reservoirs to modify the physical/chemical properties of the reservoirs to enhance the oil recovery. Up to now, the detailed MEOR mechanism is still not entirely clear due to the multiple influence factors (e.g., pH, nutrients, temperature, porosity, and permeability) on microbial growth and reproduction, as well as the lack of understanding of microbial's influencing mechanism on the oil recovery process. In this study, a Bacillus subtilis‐based MEOR process was conducted in a polymethyl methacrylate (PMMA)‐based microfluidic device to mimic the MEOR process in the reservoir. The porous microstructure based on real sandstone slice images was fabricated with laser ablation on a PMMA substrate. Two different MEOR approaches were conducted in the PMMA‐based microfluidics devices: the direct injection of displacing reagent (biosurfactant produced by bacteria) into the microfluidic chip for the oil recovery (ex‐situ), and the incubation of bacteria solution inside the chip followed with brine flooding (in‐situ). The result indicates the ex‐situ MEOR process with B. subtilis can reach a recovery rate of 38.56%, while the in‐situ MEOR process with B. subtilis reached a recovery rate of 40.27%. The proposed study provides a new tool for understanding the MEOR process, with advantages in visibility and accurate fluid control during the MEOR process.

Effect of Au film mask on antiwetting and antireflection properties of nanostructural polymer by plasma nanotexturing

Capacitively coupled radiofrequency plasma nanotexturing assisted by an Au film mask is carried out to fabricate the fluorocarbon-film decorated nanowires bundles from the semicrystalline polyethylene (PE) and amorphous PolyMethyl methacrylate (PMMA) subatrates. The spacing distance and height of the nanowires in a bundle on the PE and PMMA substrates are adjusted by the thickness of Au film mask. The complete rebound phenomenon occurs when the droplets impact with a high speed on the nanowire bundles. The nanowire bundles exhibit an improved superhydrophobicity. The narrow spacing distance between the nanowires is beneficial to the antiwetting of superhydrophobic surface. The low reflectivity of the nanowire bundles is also obtained with an incident light wavelength from 400 to 2000 nm. The antireflection property of the nanowire bundles is caused by the high height of nanowires in a bundle. The nanowire bundles on the PE and PMMA substrates prepared by the plasma nanotexturing assisted by the Au film mask have the excellent antiwetting and antireflection properties.