CO₂ 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.