The cloud points of the polymers were determined by heating 1 w/w % aqueous polymer solution (1 ml) in a water bath, with a heating rate of 1℃/min. After an initial visual observation between 20℃ to 70℃ to determine the approximate range within which the cloud point observed, the experiment was repeated in this narrower range using turbidimetry. Specifically, the polymer solution transmittance was measured as a function of temperature (Cary 3500 Compact Peltier UV-Vis System, Agilent).