화학공학소재연구정보센터
Journal of Adhesion, Vol.87, No.12, 1167-1190, 2011
Probing the Near-Surface Composition Profile of Pressure Sensitive Adhesive Films with X-Ray Reflectivity
The composition of pressure sensitive adhesive films as a function of distance from the sample surface is probed with x-ray reflectivity. A two-component statistical copolymer with ethylhexylacrylate as the majority component and methylmethacrylate representing the minority component is chosen as a sample system. Different preparation protocols are employed to tailor the near-surface composition profile. In this context, doctor-bladed films exhibit a different near-surface composition as compared with solution cast samples. For the latter case, a small surface roughness can be ensured by either using slowly evaporating solvents or reducing the solvent evaporation speed by providing an appropriate atmosphere surrounding the drying solution. For freshly prepared samples, the use of non-polar solvents in combination with the corresponding solvent vapor atmosphere leads to a surface enrichment of ethylhexylacrylate whereas a humid environment, independent of the choice of solvent, favors enrichment of the more polar methylmethacrylate. We finally show that the installed composition profiles change with time and depend on the storage conditions.