Hydration of Aqueous Polymers Investigated by Terahertz Spectroscopy and Principal Component Analysis

Hydration in aqueous solutions of poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG) was studied using terahertz spectroscopy and principal component analysis (PCA). An addition of a methyl group to a PEG repeat unit increases the number of hydration water per repeat unit. With the result of PCA, the fast relaxation process of hydration water is discussed, and the dielectric loss spectra of PEG and PPG hydration water were estimated.