PMMA Surface Research Articles

Adsorption and Morphology Analysis of Bovine Serum Albumin on a Micropillar-Enhanced Quartz Crystal Microbalance.

The adsorption of bovine serum albumin (BSA), a widely used blood plasma protein, onto poly(methyl methacrylate) (PMMA) surface is a fundamental phenomenon attracting increasing interests in molecular biology, cell culture, immunology, diagnostics, and vaccinology. The nanostructured PMMA surfaces have shown a considerable effect on the BSA adsorption process. However, the effect of microstructures (e.g., micropillars) on BSA adsorption has seldom been studied. This research reports on the development of an acoustic resonance based method to explore the adsorption of BSA proteins on PMMA micropillars in terms of surface coverage, apparent binding constants, and pH-induced morphology variation. A theoretical model is developed to understand the frequency changes of QCM induced by BSA adsorption by taking into consideration the effects of the hydrodynamic force and an equivalent BSA/liquid layer formed on the micropillar surface. In addition, it was found that the resonance of micropillars with a quartz crystal microbalance (QCM) substrate significantly influenced BSA adsorption on micropillar surfaces.

Enhanced Immobilization of Enzymes on Plasma Micro-Nanotextured Surfaces and Microfluidics: Application to HRP

The enhanced and direct immobilization of the enzyme horseradish peroxidase on poly(methyl methacrylate) (PMMA) microchannel surfaces to create a miniaturized enzymatic reactor for the biocatalytic oxidation of phenols is demonstrated. Enzyme immobilization occurs by physical adsorption after oxygen plasma treatment, which micro-nanotextures the PMMA surfaces. A five-fold enhancement in immobilized enzyme activity was observed, attributed to the increased surface area and, therefore, to a higher quantity of immobilized enzymes compared to an untreated PMMA surface. The enzymatic reaction yield reached 75% using a flow rate of 2.0 μL/min for the reaction mixture. Additionally, the developed microreactor was reused more than 16 times without affecting the enzymatic conversion yield. These results demonstrate the potential of microchannels with plasma micro/nanotextured surfaces for the rapid and facile fabrication of microfluidic enzymatic microreactors with enhanced catalytic activity and stability.

Functional Surfaces for Passive Fungal Proliferation Control: Effect of Surface Micro- and Nanotopography, Material, and Wetting Properties.

Fungal proliferation can lead to adverse effects for human health, due to the production of pathogenic and allergenic toxins and also through the creation of fungal biofilms on sensitive surfaces (i.e., medical equipment). On top of that, food spoilage from fungal activity is a major issue, with food losses exceeding 30% annually. In this study, the effect of the surface micro- and nanotopography, material (aluminum, Al, and poly(methyl methacrylate), PMMA), and wettability against Aspergillus awamori is investigated. The fungal activity is monitored using dynamic conditions by immersing the surfaces inside fungal spore-containing suspensions and measuring the fungal biomass growth, while the surfaces with the optimum antifungal properties are also evaluated by placing them near spore suspensions of A. awamori on agar plates. Al- and PMMA-based superhydrophobic surfaces demonstrate a passive-like antifungal profile, and the fungal growth is significantly reduced (1.6-2.2 times lower biomass). On the other hand, superhydrophilic PMMA surfaces enhance fungal proliferation, resulting in a 2.6 times higher fungal total dry weight. In addition, superhydrophobic surfaces of both materials exhibit antifouling and antiadhesive properties, whereas both superhydrophobic surfaces also create an "inhibition" zone against the growth of A. awamori when tested on agar plates.

Anti-Ice PMMA Surface Design and Processing

At low temperatures, PMMA surfaces are prone to ice and frost formation, which presents a significant challenge for PMMA’s efficient application in cold environments due to the difficulty in physically removing the accumulated ice. Superhydrophobic surfaces exhibit promising potential in passive anti-icing strategies. To exploit this advantage, we employed femtosecond laser technology to create six distinct microstructured PMMA surfaces, followed by surface modification using 1H,1H,2H,2H-perfluorodecyltriethoxysilane, resulting in enhanced hydrophobic and anti-icing properties. Among the tested structures, a secondary circular dot pattern achieved a remarkable contact angle of 153.7°, prolonging the freezing duration by approximately 40% at −10 °C, and reducing frost accumulation by over 50%. The ice adhesion strength was significantly reduced to 34 kPa. These findings contribute to broadening the applicability of PMMA and advancing the use of superhydrophobic surfaces in anti-icing applications.

A computational study on transition mechanism of dripping to jetting flow in a flow‐focusing geometry

Abstract2D simulations have been performed to investigate flow regimes in a flow‐focusing geometry by changing the dispersed phase and continuous phase velocities. The dispersed phase is polydimethylsiloxane (PDMS), and the continuous phase is water. Simulations have been performed in a range of oil–water viscosity ratio from 3 to 50, and interfacial tension ranges from 0.0118 to 0.002 N/m. The walls of the microchannel are considered to be poly(methyl methacrylate) (PMMA) surfaces. The contact angle (θ) of an oil droplet in the presence of water wetting the PMMA surface is 140°. Our study observed two types of flow regimes, namely dripping and jetting, by changing the dispersed phase and continuous phase velocities. The sequential time steps of void fraction contour have been presented to explore the droplet formation mechanism. The droplet pinch‐off time and jet growth time have been calculated for the dripping and jetting regime, respectively. The outcomes are summarized in the form of a flow pattern map at a viscosity ratio of 12 and interfacial tension of 0.0118 N/m, which shows the transition boundary between dripping and jetting phenomena. The simulated transition boundary agrees well with the analytical solution available in the literature. The effect of oil–water viscosity ratio and interfacial tension on droplet size is also investigated. These findings will help understand different flow regimes and their transition in a flow focusing geometry and will directly apply to microfluidic platform‐based devices.

Electric charging effects on insulating surfaces in cryogenic liquids.

This paper presents a new technique to study the adsorption and desorption of ions and electrons on insulating surfaces in the presence of strong electric fields in cryoliquids. The experimental design consists of a compact cryostat coupled with a sensitive electro-optical Kerr device to monitor the stability of the electric fields. The behavior of nitrogen and helium ions on a poly(methyl methacrylate) (PMMA) surface was compared to a PMMA surface coated with a mixture of deuterated polystyrene and deuterated polybutadiene. Ion accumulation and removal on these surfaces were unambiguously observed. Within the precision of the data, both surfaces behave similarly for the physisorbed ions. The setup was also used to measure the (quasi-)static dielectric constant of PMMA at T ≈ 70K. The impact of the ion adsorption on the search for a neutron permanent electric dipole moment in a cryogenic environment, such as the nEDM@SNS experiment, is discussed.

Mechanophysical and Anti-Adhesive Properties of a Nanoclay-Containing PMMA Denture Resin.

Poly(methyl methacrylate) (PMMA) is commonly used for dental dentures, but it has the drawback of promoting oral health risks due to oral bacterial adhesion. Recently, various nanoparticles have been incorporated into PMMA to tackle these issues. This study aims to investigate the mechanophysical and antimicrobial adhesive properties of a denture resin by incorporating of nanoclay into PMMA. Specimens were prepared by adding 0, 1, 2, and 4 wt % surface-modified nanoclay (Sigma) to self-polymerizing PMMA denture resin. These specimens were then evaluated using FTIR, TGA/DTG, and FE-SEM with EDS. Various mechanical and surface physical properties, including nanoindentation, were measured and compared with those of pure PMMA. Antiadhesion experiments were conducted by applying a Candida albicans (ATCC 11006) suspension to the surface of the specimens. The antiadhesion activity of C. albicans was confirmed through a yeast-wall component (mannan) and mRNA-seq analysis. The bulk mechanical properties of nanoclay-PMMA composites were decreased compared to those of pure PMMA, while the flexural strength and modulus met the ISO 20795-1 requirement. However, there were no significant differences in the nanoindentation hardness and elastic modulus. The surface energy revealed a significant decrease at 4 wt % nanoclay-PMMA. The antiadhesion effect of Candida albicans was evident along with nanoclay content in the nanocomposites and confirmed by the reduced attachment of mannan on nanoclay-PMMA composites. mRNA-seq analysis supported overall transcriptome changes in altering attachment and metabolism behaviors on the surface. The nanoclay-PMMA materials showed a lower surface energy as the content increased, leading to an antiadhesion effect against Candida albicans. These findings indicate that incorporating nanoclay into PMMA surfaces could be a valuable strategy for preventing the fungal biofilm formation of denture base materials.

Three‐dimensional simulation of dripping and jetting phenomenon in a flow‐focusing geometry

Abstract3D simulations have been achieved on a flow‐focusing geometry employing the VOF method to study the consequence of viscosity, surface tension, wettability, and geometry on drop generation for the dripping regime. Here the dispersed phase is the PDMS oil (polydimethylsiloxane), and the continuous phase is the water. Simulations were performed at different oil‐to‐water viscosity ratios of 3, 12, 27, and 50. The interfacial tension between PDMS oil and water is 0.0118 N/m. It has been abridged to 0.008 N/m, 0.005 N/m, and 0.002 N/m, and simulations were performed. The walls of the microchannel are considered to be PMMA surfaces. The contact angle of an oil droplet on the PMMA surface in the presence of water is 140°. The effect of wettability was shown at various contact angles (angle created by water droplet on the PMMA surface in the presence of oil) of 0°, 40°, 90°, 135° and 180°. The frequency of droplet generation (1/s), non‐dimensional droplet length (L/Wc), droplet volume (nl), and droplet velocity (m/s) have been calculated for each of the cases. A flow pattern map has been industrialized classifying the dripping and jetting regimes. A comparison between normal geometry and two constricted geometries (having different orifice lengths) based on the frequency of droplet, non‐dimensional drop length, drop volume, and drop velocity has been made for both dripping and jetting regimes. Prediction of simulated non‐dimensional droplet length has also been made using dimensional analysis.

Generating Stable Nitrogen Bubble Layers on Poly(methyl methacrylate) Films by Photolysis of 2-Azidoanthracene.

2-Azidoanthracene (2N3-AN) can act as a photochemical source of N2 gas when dissolved in an optically transparent polymer such as poly(methyl methacrylate) (PMMA). Irradiation at 365 or 405 nm of a 150 μm-thick polymer film submerged in water causes the rapid appearance of a surface layer of bubbles. The rapid appearance of surface bubbles cannot be explained by normal diffusion of N2 through the polymer and likely results from internal gas pressure buildup during the reaction. For an azide concentration of 0.1 M and a light intensity of 140 mW/cm2, the yield of gas bubbles is calculated to be approximately 40%. The dynamics of bubble growth depend on the surface morphology, light intensity, and 2N3-AN concentration. A combination of nanoscale surface roughness, high azide concentration, and high light intensity is required to attain the threshold N2 gas density necessary for rapid, high-yield bubble formation. The N2 bubbles adhered to the PMMA surface and survived for days under water. The ability to generate stable gas bubbles "on demand" using light permits the demonstration of photoinduced flotation and patterned bubble arrays.

Enhanced mechanical, electrical, thermal, and optical properties of poly(methyl methacrylate)/copper oxide nanocomposites for flexible optoelectronic devices via in‐situ polymerization technique

AbstractPolymethyl methacrylate (PMMA) with varied compositions of copper oxide (CuO) nanoparticles was synthesized using in‐situ free radical polymerization. UV–visible, FT‐IR, XRD, FE‐SEM, DSC, and TGA were employed to examine their structure, morphology, and thermal properties. The broadening and intensification of UV absorption, as well as the shift in IR peaks of PMMA with the addition of CuO, confirm their interactions. The reduction in optical bandgap values with the reinforcement of nanofillers confirms the existence of intermediate energy bands in nanocomposites. XRD indicated that polymerization with CuO reduced the amorphous nature of PMMA. The FE‐SEM image revealed that the dispersion of CuO altered the nonporous, rough surface of PMMA into a homogeneous shape. The reinforcement of CuO enhanced the thermal stability and glass transition temperature of PMMA. The mechanical strength, modulus, impact strength, and rigidity of PMMA were significantly improved through in‐situ polymerization. The electrical property analysis revealed that the AC conductivity increased with frequency, temperature, and filler content. The reduction in activation energy of AC conductivity with temperature points toward their semiconducting nature. PMMA/CuO nanocomposites with higher tensile strength, lower bandgap energy, higher conductivity, and thermal properties can be used to make flexible optoelectronic devices.Highlights A series of PMMA/CuO nanocomposites were synthesized and characterized. Enhanced optical property, thermal stability, and glass transition temperature. Possess excellent dielectric constant and AC conductivity. Mechanical strength and impact resistance of PMMA were greatly enhanced. A promising material for flexible optoelectronic and power storage applications.

Rapid-release reversible bonding of PMMA-based microfluidic devices with PBMA coating.

PMMA-based microfluidics have been widely used in various applications in biological and chemical fields. In the fabrication process of PMMA-based microfluidics, the substrate and cover plate usually need to be bonded to enclose the microchannel. The bonding process could be permanent or reversible. In some application scenarios, reversible bonding is needed to retrieve the samples inside the channel or reuse the chip. Current reversible bonding methods for PMMA-based microfluidics usually have drawbacks on bonding strength and contaminations from the adhesives used in the bonding process. In this study, a new approach is proposed for the reversible bonding of PMMA-based microfluidics, a layer of PBMA (with a very similar structure to PMMA) was coated on the surface of PMMA and then use the thermal fusion method to achieve the bonding with a high bonding strength, a tensile bonding strength of around 0.8MPa was achieved. For debond process, a rapid temperature drop will trigger the immediate release of the bonding within several seconds. Detailed bonding strength measurement and biocompatibility tests were also conducted in this study. The proposed bonding method could have wide application potential in the fabrication of PMMA-based microfluidics.

Design of Versatile Top‐Down Transfer by Thermal Release Tape/Poly(methyl methacrylate) (TRT/PMMA) Bi‐Supporting Layers Toward All‐Transfer Transition Metal Dichalcogenide Material Based Transistor Arrays

A top‐down transfer process is developed via a rolling process associated with thermal release tape/poly(methyl methacrylate) (PMMA) bi‐supporting layers to realize large‐scale transfer processes on transition metal dichalcogenide materials. A 2‐inch MoS2 thin film transferred on SiO2/Si substrates with high integrity and a yield of ≈99% can be successfully achieved via the proposed process. MoS2‐based transistors with a transferred Au thin film as the contact electrode indicate a lower contact resistance of 8.4 kΩ with improved mobility and a higher on/off ratio compared with that of the MoS2‐based transistors with the evaporated Au thin film as the contact electrode. By applying the difference in adhesion force between metal oxides and metal on MoS2 and PMMA surfaces, the selective transfer of MoS2 films can be demonstrated. Furthermore, all‐transferred MoS2‐based transistor arrays are demonstrated by combining the selectively transferred MoS2 film as the channel material and the transferred Au thin films as the contact electrode, which results in uniform electrical properties featuring a carrier mobility of 10.45 cm2 V−1 s−1, a subthreshold swing of 203.94 mV dec−1, a normalized Ion of 8.3 μA μm−1, and an on/off ratio of 105.

Surface Functionalization and Escherichia coli Detection Using Surface-Enhanced Raman Spectroscopy Driven by Functional Organic Polymer/Gold Nanofilm-Based Microfluidic Chip.

In this work, a microfluidic prototype based on polymeric materials was developed to monitor surface processes using surface-enhanced Raman spectroscopy (SERS), keeping the reagents free of environmental contamination. The prototype was fabricated on poly(methyl methacrylic acid) (PMMA). A micrometric membrane of a functional organic polymer (FOP) based on p-terphenyl and bromopyruvic acid monomers was formed on the PMMA surface to promote the formation of metal nanoclusters. Au nanosized film was deposited on the FOP membrane to give rise to the SERS effect. A microchannel was formed on another piece of PMMA using micromachining. A representative 3D model of the prototype layer arrangement was built and simulated in COMSOL Multiphysics® to approximate the electric field distribution and calculate the power enhancement factor as the Au film changes over time. The fabrication process was characterized using UV-visible and Raman spectroscopies and XPS. The prototype was tested using a Raman microscope and liquid solutions of cysteamine and Escherichia coli (E. coli). The simulation results demonstrated that the morphological characteristics of the Au layer give rise to the SERS effect, and the power enhancement factor reaches values as high as 8.8 × 105 on the FOP surface. The characterization results showed the formation of the FOP and the Au film on PMMA and the surface functionalization with amine groups. The Raman spectra of the prototype showed temporal evolution as different compounds were deposited on the upper wall of the microchannel. Characteristic peaks associated with these compounds were detected with continuous monitoring over time. This prototype offers many benefits for applications like monitoring biological processes. Some advantages include timely surface evaluation while avoiding environmental harm, decreased use of reagents and samples, minimal interference with the process by measuring, and detecting microorganisms in just 1 h, as demonstrated with the E. coli sample.

Inhibition of non-specific protein adsorption on PMMA surface: The role of surface modification

Mitigating non-specific adsorption (NSA) occurring on the surface of microfluidic devices plays a critical role in the detection of early protein biomarkers for clinical diagnosis. Surface-modified methods commonly used in the formation of microfluidic channels include BSA coating, PEG grafting, and Plasma cleaning. The surface composition and microstructure of PMMA surfaces were characterized by Fourier transfer infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), water contact angles (CA), and atomic force microscopy (AFM) measurements. The NSA on surfaces of bovine serum albumin (BSA) labeled with fluorescein isothiocyanate (FITC) were investigated by microfluidics and fluorescence microscopy. The results showed that the hydrophobicity of the PMMA surface was enhanced after modification with PEG. We further evaluated their anti-protein adsorption properties under a mild alkaline (PH 7.4) condition, including concentration, reaction time, and sample volume. The BSA coating had the best anti-protein adsorption effect, reaching over 87.6%. The anti-protein adsorption effect of the plasma cleaning method is slightly inferior to that of BSA coating, at 86.1%, but the modification process is simpler and faster. Due to the insufficient stability of PEG, its resistance to protein adsorption decreases as the concentration increases.

Emulsion Polymerisation of Poly(Methyl Methacrylate)-Grafted-Graphene Oxide (PMMA-GO): Effect of Surfactant Concentration on Colloidal Stabilization

Graphene oxide (GO) exhibits a wide range of outstanding mechanical, electrical, and physical characteristics, and it is of substantial interest to impart such qualities onto polymeric materials such as poly (methyl methacrylate) PMMA for wider specialized functionalization. The attention of this work is on the development of emulsion polymerization procedure to prepare PMMA-GO nanocomposite and the effect of sodium dodecyl sulphate (SDS) surfactant dosages incorporated during the polymerization, on the effect of PMMA surface interactions in oil. The grafting efficiency is quantified using the Fourier-transform infrared spectroscopy (FTIR), and the effect of surfactant concentration on PMMA-GO stability is examined using UV-Visible spectroscopy, zeta potential and particle size analyses using the Malvern Zetasizer. The surfactant free emulsion has a better stabilization in terms of zeta potential analysis compared to emulsion of PMMA-GO with 0.32, and 0.4 wt. % of SDS. The polymerized PMMA-GO can be used as a model system to alter wax crystallization at low temperatures in oil and gas industries.

Assessment of Polydopamine to Reduce Streptococcus mutans Adhesion to a Dental Polymer.

Bacterial adhesion to the surface of materials is the first step in biofilm formation, which will lead to conditions that may compromise the health status of patients. Recently, polydopamine (PDA) has been proposed as an antibacterial material. Therefore, the objective of the current work was to assess and compare the adhesion of Streptococcus mutans to the surface of poly(methyl methacrylate) (PMMA) discs that were modified using PDA following a biomimetic approach versus smooth PDA-coated PMMA surfaces. In addition, an assessment of the growth inhibition by PDA was performed. PMMA discs were manufactured and polished; soft lithography, using the topography from the Crocosmia aurea leaf, was used to modify their surface. PDA was used to smooth-coat PMMA discs by dip-coating. The growth inhibition was measured using an inhibition halo. The surfaces were characterized by means of atomic force microscopy (AFM), the contact angle (CA), and Fourier-transform infrared spectroscopy (FTIR). Polydopamine exhibited a significant antibacterial effect when used directly on the S. mutans planktonic cells, but such an effect was not as strong when modifying the PMMA surfaces. These results open the possibility of using polydopamine to reduce the adhesion and growth of S. mutans, which might have important consequences in the dental field.

Experimental Investigation and Mathematical Modeling of Heat Distribution on a Laser-Treated PMMA Surface

Experimental Investigation and Mathematical Modeling of Heat Distribution on a Laser-Treated PMMA Surface

New Theoretical Model for Mass Sensitivity of Love Wave Sensors

In this work we analyse basic characteristics of Love wave sensors implemented in waveguide structures composed of a lossy viscoelastic surface layer deposited on a lossless elastic substrate. It has to be noted that Love wave sensors working at ultrasonic frequencies have the highest mass density sensitivity $S_σ^(v_p )$ among all known ultrasonic sensors, such as QCM, Lamb wave or Rayleigh wave sensors. In this paper we have established an exact analytical formula for the mass density sensitivity $S_σ^(v_p )$ of the Love wave sensors in the form of an explicit algebraic expression. Subsequently, using this developed analytical formula, we compared theoretically the mass density sensitivity $S_σ^(v_p )$ for various Love wave waveguide structures, such as: (1) lossy PMMA surface layer on lossless Quartz substrate and (2) lossy PMMA on lossless Diamond substrate. The performed analysis shows that the mass density sensitivity $S_σ^(v_p )$ (real and imaginary part) for a sensor with a structure PMMA on Diamond is five times higher than that of a PMMA on Quartz structure. It was found that the mass density sensitivity $S_σ^(v_p )$ for Love wave sensors increases with the increase of the ratio: bulk shear wave velocity in the substrate to bulk shear wave velocity in the surface layer.

Pendant Modification of Poly(methyl methacrylate) to Enhance Its Stability against Photoirradiation.

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.

YÜKSEK FREKANSLI RF PLAZMALAR İLE PMMA FİLMLERİNİN ISILABİLİRLİĞİNİN İYİLEŞTİRİLMESİ

Poly(methyl methacrylate) (PMMA) has a wide variety of applications due to its attractive physical and optical properties. Due to its hydrophobic (water-repellent) character, the surface of PMMA should be modified before being used in applications. In this study, the surface of PMMA films were modified by 40.68 MHz high frequency CCP (capacitive-coupled plasma) RF system with nitrogen (N) and argon (Ar) gases. The experiments carried out under various plasma powers while the pressure and treatment time were kept constant. The wettability of the plasma treated surfaces was analyzed with contact angle and surface free energy (SFE) measurements. Also, the change in the chemical structure of the surfaces was investigated with X-ray photoelectron spectroscopy (XPS). The results showed that all plasma treatments enhanced the hydrophilicity of the surfaces and the lowest contact angle values obtained at high plasma power. The total SFE of the treated surfaces increased with power and the main contribution to total SFE came from polar components. The polar groups formation on the surface after plasma treatment was proved with XPS results. Hence, it was found that high frequency CCP RF plasmas can be used effectively to obtain hydrophilic polymer surfaces.