Aspects concerning the temperature influence on the polymer/polymer interactions between poly(aspartic acid) and poly(ethylene glycol)

The purpose of this study is to investigate the temperature influence on the complex formation in aqueous solutions of mixtures between a nonionic polymer, i.e., poly(ethylene glycol) (PEG), and a polyelectrolyte type polymer, namely poly(aspartic acid) (PAS). The PAS/PEG/water colloidal systems were studied as a function of the PEG chain length at different temperatures: 22 °C, 26 °C, 30.7 °C and 37 °C, temperatures corresponding to the storage and use conditions of the systems. The changes of the electrokinetic and rheological properties were revealed and correlated with the information given by Fourier Transform Infra-Red Spectroscopy (FTIR) studies in order to underline the interpenetration process between PAS and PEG macromolecular chains. The study evidences the unfavorable effect of the temperature upon interpolymeric complex formation. Both homopolymers are biocompatible and their resulting interpolymeric complex can be regarded as a network with potential bioapplications.