Surface feature of PMMA films on NiTi alloy substrate by the spin coating method

Abstract

Polymethylmethacrylate (PMMA) films are deposited on NiTi shape memory alloy by using the spin coating method. Different ratios of PMMA powder to Toluene were mixed with magnetic stirrer for a duration of 12 h. The various concentrations of solution (mol. %) were used for the spin coating method on the substrate NiTi to produce thin films. The samples were cured in various environment from room to furnace temperature. The surface features of PMMA films were investigated by using an optical microscope. Thermal and mechanical behavior of the NiTi substrate and composites was and studied in the paper. The spin coating and post-processing conditions determined the surface morphology that is featureless or dominate by pinholes and other surface defects. The spin-coated coating at 200 rpm improved film surfaces with 4 mol % PMMA solution. Surface defects in the form of pinholes appear on the surface of the film obtained by spin-coating at 3200 rpm from 8 mol % solution and post-baked at 80 °C for 60 min on a hot plate in an oven inside a vacuum chamber. Different coating properties depends on the preparation parameters by spin coating and thermal and microstructural, mechanical properties are explained and discussed in the paper.