Interfacial Chemistry of Poly(methyl methacrylate) Arising from Exposure to Vacuum-Ultraviolet Light and Atomic Oxygen

Abstract

We herein report on the chemical and physical changes that occur in thin films of poly(methyl methacrylate), PMMA, induced by exposure to high-energy vacuum ultraviolet radiation and a supersonic beam of neutral, ground electronic state O((3)P) atomic oxygen. A combination of in situ quartz crystal microbalance and in situ Fourier-transform infrared reflection-absorption spectroscopy were used to determine the photochemical reaction kinetics and mechanisms during irradiation. The surface morphological changes were measured with atomic force microscopy. The results showed there was no enhancement in the mass loss rate during simultaneous exposure of vacuum ultraviolet (VUV) radiation and atomic oxygen. Rather, the rate of mass loss was impeded when the polymer film was exposed to both reagents. This study elucidates the kinetics of photochemical and oxidative reaction for PMMA, and shows that the synergistic effect involving VUV irradiation and exposure to ground state atomic oxygen depends substantially on the relative fluxes of these reagents.

Photochemical Molecular Tailoring for Efficient Diffusion and Reorganization of Organic Nanocrystals for Ultra-Flexible Organic Semiconductor Arrays

“…The line scan profile across photochemically patterned PMMA layer using atomic force microscopy (AFM) shows a thickness reduction of DUV‐irradiated PMMA comparing to pristine region. The significant thickness reduction of DUV exposed region was attributed to the photochemical condensation, defragmentation, and subsequent volatile species removal within the PMMA layer . Particularly, the DUV irradiation can give rise to the photochemical reaction both at the surface and within the bulk of PMMA.…”

Determination of the sticking coefficient and scattering dynamics of water on ice using molecular beam techniques

“…A schematic is shown in Fig. 15 The Au(111) single crystal was mounted on a five-axis manipulator and could be cooled below 120 K with liquid N 2 and radiatively heated above 1000 K to clean the Au(111) substrate. A Rh(111) single crystal was mounted on a manipulator that allows for the adjustment of the incident polar angle ( I ), was cooled with liquid N 2 , and resistively heated.…”

PMMA Surface Functionalization Using Atmospheric Pressure Plasma for Development of Plasmonically Active Polymer Optical Fiber Probes

“…ion bombardment, where the contact angle increases in contact with water during measurement. These observations suggest scission or fragmentation of polymer chains due to plasma treatment and possibly photochemical processes [40,41] and subsequent loss of functional groups formed on these chains with DI wash. This finding explains the poor adsorption of AuNF on plasma treated POF probe as the aqueous AuNF solution may have removed the surface functional groups during the incubation of the probe.…”