Multidimensionally stimuli‐responsive phase transition of aqueous solutions of poly((N,N‐dimethylamino)ethyl methacrylate) and poly(N,N‐dimethyl‐N‐(methacryloyl)ethyl ammonium butane sulfonate)

Free radical polymerization of N,N‐(dimethylamino)ethyl methacrylate and N,N‐dimethyl‐N‐(methacryloyloxy)ethyl ammonium butane sulfonate was carried out to prepare PDMAEMA and PDMABS. Proton nuclear magnetic resonance spectroscopy indicated that both PDMAEMA and PDMABS exhibited an electrolyte‐responsive conformational dynamics in D2O of different ionic strength. PDMAEMA, as a polybase, and PDMABS, as a polysulfobetaine, exhibited a series of multidimensional stimuli‐responsive phase transition behaviors. Adding NaCl would decrease the phase transition temperature (TPT) of their aqueous mixtures, because of polyelectrolyte effect for PDMAEMA and anti‐polyelectrolyte effect for PDMABS, respectively. For PDMAEMA, a low pH would facilitate the dissolution; on the other hand, for PDMABS, a maximum TPT was achieved in neutral media.