1H-NMR studies on the volume phase transition of DNA-modified pNipmam microgels

Abstract

DNA functionalized pNipmam microgels, which have recently been introduced, are examined at different concentrations of sodium chloride and in PBS solutions via temperature dependent ¹H-NMR measurements and are compared to pure pNipmam microgels. We show that the DNA modification shifts the volume phase transition temperature towards lower temperatures and the addition of salt and PBS further supports this effect in both materials. Thermodynamic values, i.e. enthalpy, entropy and Gibbs free energy, are determined via a non-linear fit which can be applied directly to the measurement data without further linearization.