Methyl Methacrylate Thin Films Research Articles

The Correlation of Plasma Characteristics to the Deposition Rate of Plasma Polymerized Methyl Methacrylate Thin Films in an Inductively Coupled Plasma System

A plasma system attached with one internal coil (for generating inductively coupled plasma) and two sputtering carbon targets was set up to deposit PP-MMA (plasma polymerized methyl methacrylate) thin films. PP-MMA was used as a model material in the present study. In the experiment, the working pressure and Ar/MMA flow ratio were varied, which resulted in the change in plasma conditions as well as the deposition rates. The optical emission spectroscopy (OES) method was applied to identify the presence of the excited species related to the fragmented monomer. In addition, the electron temperature and electron density were determined using the modified Boltzmann plot and line-ratio method, according to the measured OES spectra. The deposition rate of the PMMA film was then correlated with the determined plasma characteristics. To determine the vibrational modes of the deposited PP-MMA films, Fourier transformed infrared spectrometry (FTIR) was used. The highest deposition rate of PP-MMA could be obtained with the optimized working pressure and Ar/MMA volume ratio. This could be related to the plasma characteristics that contribute to the fragmentation of the monomer in the plasma.

Preparation of poly methyl methacrylate thin film by solution casting method to study its ultrasonic velocity

Polymers are long chain giant organic molecules are assembled from many smaller molecules called monomers. The work reflects the preparation of poly methyl methacrylate thin film by solution casting method. The XRD of PMMA/ZrO2 polymer is taken to confirm the structure and nature of material. Furthermore, it is characterized by finding the ultrasonic velocity at different concentration of ZrO2 and at different temperature keeping the frequency same.

Linear Optical Properties of Bromocresol Green Dye Doped Poly Methyl Methacrylate Thin Films

In this study, we investigated the effect of Bromocresol green dye (BCG) of the PMMA thin films optical properties. Films of Poly Methyl Methacrylate doped by 10% BCG doping ratio to prepared two concentrations 2x10 -4 and 6x10 -4 M of PMMA-BCG dye were deposited on glass substrate using free casting method at room temperature. The optical properties of the films were determined using UV-Visible absorbance and transmittance spectra at the 300 - 900 nm wavelength range. The linear absorption coefficient and the extinction coefficient were calculated. The results showed that the optical properties were increasing by increasing the dye concentration, while the optical energy gap was decreasing with the doping. Also from the linear optical properties result the PMMA-BGC thin films are a promised materials for nonlinear optics applications.

Process Condition Considered Preparation and Characterization of Plasma Polymerized Methyl Methacrylate Thin Films for Organic Thin Film Transistor Application

Process Condition Considered Preparation and Characterization of Plasma Polymerized Methyl Methacrylate Thin Films for Organic Thin Film Transistor Application

Process Condition Considered Preparation and Characterization of Plasma Polymerized Methyl Methacrylate Thin Films for Organic Thin Film Transistor Application

Plasma polymerized methyl methaclylate (ppMMA) thin films were prepared with various process conditions such as inductively coupled plasma (ICP) power, substrate bias power, working pressure, substrate heating temperature, substrate position, and monomer flow rate. Thickness, surface morphology, dielectric constant, and leakage current of the ppMMA thin films were investigated for application to organic thin film transistor as gate dielectric. Deposition rate of over 8.6 nm/min, dielectric constant of 3.4, and leakage current density of 8.9 ×10-9 A/cm-2 at electric field of 1 MV/cm were achieved for the ppMMA thin film prepared at the optimized process condition: plasma power of RF 100 W; Ar flow rate of 20 sccm; working pressure of 5 mTorr; substrate temperature of 100 °C; substrate position of 100 mm. The ppMMA thin film was then applied to pentacene based organic thin film transistor (OTFT) device fabrication. The OTFT device with 80 nm thick pentacene semiconductor layer showed field effect mobility of 0.144 cm2 V-1 s-1 and threshold voltage of -1.72 V.

Preparation and Characterization of Plasma Polymerized Methyl Methacrylate Thin Films as Gate Dielectric for Organic Thin Film Transistor

Plasma polymerized methyl methacrylate (ppMMA) thin films were deposited by plasma polymerization technique with different plasma powers and subsequently thermally treated at temperatures of 60 to <TEX>$150^{\circ}C$</TEX>. To find a better ppMMA preparation technique for application to organic thin film transistor (OTFT) as dielectric layer, the chemical composition, surface morphology, and electrical properties of ppMMA were investigated. The effect of ppMMA thin-film preparation conditions on the resulting thin film properties were discussed, specifically O-H site content in the pMMA, dielectric constant, leakage current density, and hysteresis.

Molecular Dynamics Investigation into the Effect of Temperature on the Structure and Properties of Methyl Methacrylate Thin Films on a Au(111) Surface

An atomistic modeling approach is performed to investigate the effect of temperature on the structural properties of the MMA (methyl methacrylate) thin film and a Au(111) surface. The density profile and orientation of the MMA molecule in the thin film have been analyzed. We found that there is a significant effect on the density profile and orientation of the MMA molecule in the region near the interface between the thin film and the Au substrate. As the temperature increases, the density clearly decreases in this region; in addition, the orientation of the MMA molecule also changes. Next, we calculated and examined the relationships between the stress, surface tension, and free energy and the density profile. Finally, we analyzed the influence of temperature on the interaction strength between the MMA molecules and between the MMA molecules and the Au(111) surface. We found that the influence of the interaction strength is more significant between MMA molecules than between MMA molecules and the Au(111) surface.

Carbon dioxide sorption in conventional and plasma polymerized methyl methacrylate thin films

CO2 sorption isotherms are reported for plasma polymerized methyl methacrylate (ppMMA) and the conventionally polymerized analog, poly(methyl methacrylate) (PMMA). The isotherms are measured at temperatures ranging from 20 to 95°C and analyzed using the Dual-Mode sorption model. In the lower temperature range, the magnitude of the Henry's law (kD) and the coupled Langmuir component parameters (C′Hb) for both materials are similar. The expected collapse of the Langmuir sorption mode in conventional PMMA near the glass transition temperature is clearly observed. However, the Langmuir component in the plasma polymerized material does not diminish in the same manner as that for the conventional polymer analog. In contrast with the ppMMA, the PMMA materials are shown to exhibit significant dilation for extended conditioning times at high CO2 pressures. The response of the isotherms for the two materials to ‘quench’ and ‘slow cool’ thermal conditioning protocols are similar, but small.

Vapor sorption in plasma polymerized vinyl acetate and methyl methacrylate thin films

Vapor sorption isotherms of vinyl acetate (VAc) and methyl methacrylate (MMA) plasma polymer thin films are measured and compared with those for cast films of the conventionally polymerized analogs. Sorption isotherms are collected for methanol, acetone, hexane, and water at 30°C using a Quartz Crystal Microbalance (QCM). The isotherms are analyzed using both Dual-Mode and Flory–Huggins sorption models. In general, plasma polymer sorption isotherms approximate those of the conventional polymer analogs, but exhibit an enhanced Langmuir-type sorption component at low activity. Accordingly, Dual-Mode model parameters show roughly equivalent Henry's Law solubility coefficients with the Langmuir-type capacity parameters (CH′) being 5–20-fold higher than those for the conventional polymer materials.

Multipolar molecules and multipolar fields: probing and controlling the tensorial nature of nonlinear molecular media

A general class of multipolar molecules is introduced in the context of quadratic nonlinear optics by way of extension of the more specific cases of dipolar and octupolar molecules. An adequate irreducible tensor formalism permits us to define rotationally invariant molecular features that couple to corresponding field tensor components, thereby enabling us to account for a variety of coherent and noncoherent processes such as harmonic light (hyper-Rayleigh) scattering, coherent second-harmonic generation in electrically poled media, and the recently proposed optical poling scheme. Experiments in both harmonic light scattering in solution (for some multipolar molecules) and optical poling (in Disperse Red 1–methyl methacrylate thin films) are analyzed in light of this model. A general tensorial permutation lemma of broad validity allows nonlinear light–matter interactions to be condensed in a statistical medium in compact rotationally invariant expressions: The main tensorial symmetry features for both molecular susceptibility and read–write field polarization tensors that jointly drive these interactions are clearly revealed.

Control of the polarization dependence of optically poled nonlinear polymer films

We demonstrate the possibility of controlling the symmetry properties of photoinduced chi((2)) macroscopic susceptibility in polymer films. Ellipsometric adjustment of the write beams allows one to monitor the macroscopic chi((2)) symmetry from a dipolar to an octupolar configuration. Experimental results are in agreement with an irreducible spherical tensor-based model jointly applied to the molecular beta hyperpolarizability and field tensors. We found a purely octupolar polarization-independent photoinduced second-harmonic-generation response in a Dispersed Red 1-methyl methacrylate thin film. Such a configuration, as generated by an octupolar tensor write field tensor made up of counterclockwise circularly polarized omega and 2omega beams, is not within the reach of the classical electric-field poling technique.

Plasma polymerized methyl-methacrylate as an electron-beam resist

Plasma polymerized methyl-methacrylate thin film was formed on a glass substrate coated with chromium as a resist for electron-beam lithography. The polymerizations were conducted at two discharge frequencies of 13.56 MHz and 5 KHz using a capacitively coupled discharge electrode system in a bell-jar-type reactor. Delineations were carried out using an electron beam whose diameter and acceleration voltage were 0.5 μm and 20 kV, respectively. As a test pattern, 25 pairs of parallel lines and spaces each having a 10-μm width were delineated in a rectangular area of 0.5×0.5 mm2. Each line of 10-μm width was depicted by sweeping over using the electron beam with 20 repetitions. The patterns were developed on the chromium by CCl4 plasma etching.