G. Chen and A. S. Hoffman, “Graft Copolymers That Exhibit Temperature-Induced Phase Transition over a Wide Range of pH,” Nature, Vol. 373, No. 6509, 1995, pp. 49- 52. http://dx.doi.org/10.1038/373049a0

has been cited by the following article:

• TITLE: Thermo- and pH-Responsive Hydrogels Based on N-Isopropylacrylamide and Allylamine Copolymers

  AUTHORS: Victoria Konovalova, Yuri Samchenko, Ganna Pobigai, Anatoly Burban, Zoya Ulberg

  KEYWORDS: Thermo-Responsive Hydrogels; Copolymer Hydrogels; Allylamine Hydrochloride;N-Isopropyl-Acrylamide; The Parameter of Flory

  JOURNAL NAME: Soft, Vol.2 No.4, December 6, 2013

  ABSTRACT: The thermo- and pH-responsive hydrogels were synthesized via copolymerization of N-isopropylacrylamide and al-lylamine hydrochloride monomers. The equilibrium swelling of the hydrogels was studied as a function of temperature and pH in aqueous solutions. It was shown that controlled alteration of the hydrogel phase transition temperature can be achieved by changing their composition and pH of the environment. Increase in content of hydrophilic allylamine from 10 to 60 wt% in monomer mixture causes a shift of the phase transition temperature from 35oC to 47oC. Hydrogels with N-isopropylacrylamide/allylamine hydrochloride mass ratio of 3:2 show the highest pH-response. Values of average molecular weight between polymer cross-links, , and Flory parameter, χ, were calculated using temperature dependences of the equilibrium swelling of the synthesized hydrogel.