CO 2 transport behavior in poly(fluoroalkyl acrylate) and poly(fluoroalkyl methacrylate): a comparative study of fluoropolymer structure–property relationships

This study examines the CO2 transport behavior of poly(fluoroalkyl acrylate) (PFA) and poly(fluoroalkyl methacrylate) (PFMA) thin films. Using time-resolved attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and a quartz crystal microbalance (QCM), we quantified CO2 diffusivity and solubility, linking these properties to the polymer side-chain architecture. The results demonstrate that PFMA exhibits lower CO2 permeability than PFA at comparable side-chain lengths, owing to restricted chain mobility caused by the α-methyl backbone of PFMA. Additionally, longer fluorinated side chains increase CO2 diffusivity while simultaneously reducing solubility owing to weaker polar interactions with CO2. Overall, the CO2 permeability of PFA surpasses that of the PFMA series because of its higher diffusivity. These findings highlight the intricate balance between diffusivity and solubility governed by the molecular structure.