Effect of glass transition temperature (T_g) on the absorption of bisphenol A in poly(acrylate)s thin films

The absorption of bisphenol A (BPA) in several poly(acrylate)s thin films such as poly(n-butyl methacylate) (PBMA) and poly(methyl methacrylate) (PMMA) as well as in a non-acrylate polymer, deuterated polystyrene (dPS) has been investigated as a function of temperature by infrared reflection absorption spectroscopy (IRRAS) and sum frequency generation (SFG) measurements. IRRAS results show that BPA was absorbed in the bulk of both PBMA and PMMA when the absorption temperature was higher than the glass transition temperature (T _g) of the polymer. The absorption rate of BPA became very low at the temperature lower than the T_g. Furthermore, SFG measurement, which is known as a surface sensitive vibrational spectroscopy, demonstrated that BPA was adsorbed on the surfaces of PMMA and PBMA even at the temperature lower than their T_g. However, absorption of BPA was observed neither in the dPS bulk nor on its surface even at the temperature higher than its T_g. IRRAS measurements show that the hydrogen bonding was formed between the poly(acrylate)s and BPA but was not observed between the dPS and BPA. We conclude that not only the T_g but also the chemical interaction between the polymer and BPA plays important roles in the BPA absorption process.