While S0 phase separates above 65 °C, the Tcp of S12 shifts to 30 °C. Further increasing the thionation degree, decreases the Tcp to below 20 °C. S20 was found to be almost at the limit of water solubility, with a cloud point of 8 °C at the concentration of 5 g/L. Almost no hysteresis is observed between heating and cooling cycles (Figure ), which could be attributed to the fully amorphous character of the polymers, as shown in the DSC thermograms. For example, hysteresis can be mostly observed for the polymers which can make intramolecular hydrogen bonding (e.g. PNIPAM) which is not the case for the polymers with tertiary amide/thioamide repeating units. Additionally, it is important to mention that the samples S3, S8 and S12 were not completely clear in their dissolved state, especially at high concentrations. This could be caused by remaining impurities, however, according to NMR spectra, samples show no impurity signals (Figure -S11). This behavior may be attributed to time dependent microphase separation of thioamide repeating units, due to decreased hydrogen bonding with water, results in less hydration and increased amphiphilicity.