Poly(tert butyl acrylate) (PTBA) is found to exhibit enhanced mobility when spun cast into thin films or impregnated into cylindrical anodic aluminum oxide (AAO) nanoscale pores, In a thin film configuration, the glass transition temperature of 20 nm thick PTBA is found to decrease almost 20 degrees C compared to the bulk. Consistent with this mobility increase, an increased volume fraction of interphase polymer leads to at least a 2.4 times viscosity reduction when PTBA is impregnated in 100 nm pores versus 200 nm pores. Such increases in mobility result in a 15-fold increase in CO2 permeability for an AAO confined geometry compared to a bulk film. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 434-441, 2010