The Effect Hydrophilic/Hydrophobic Interaction of 2-((Dimethylamino)methyl)-4-formyl-6 methoxyphenyl Acrylate and 4-Acetylphenyl Acrylate Monomers on the Phase Transition Temperature of N-isopropylacrylamide Terpolymers

To achieve functional polymer with thermo-pH responsivity, new functional monomers have been prepared. One is based on vanillin as a renewable material of 2-((dimethylamino)methyl)-4-formyl-6-methoxyphenyl acrylate (DMAMVA), and the other based on 4-hydroxyacetophenone 4-acetylphenyl acrylate (APA). The new monomers were evaluated with 1 H, 13 C NMR, FTIR, and UV. The next step was focused on preparing a new series of thermo-pH functional polymer with three different molar concentrations of DMAMVA and one molar concentration of APA; they were evaluated by 1 H NMR and FTIR. The effect of hydrophilic/hydrophobic groups based on the new monomers on the phase separation and the lower critical solution temperature of N -isopropylacrylamide has been investigated using two methods; the turbidity method by UV–Vis spectroscopy in which the change in transmittance has been taken with the temperature of the polymer solution. On the other hand, micro-DSC was used to recode the transition temperature at the onset value of the thermogram. Moreover, polymers have been fully investigated by GPC for molecular weight, DSC for glass temperature, XRD for the degree of crystallinity and SEM for surface morphological features. This study will be progressed in the future as the preparation of post-polymerization and formation of hydrogel for targeting biomolecules and their responsivity to both temperature and pH. Graphic Abstract