Polyampholytic hydrogels

Piirma I. Polyelectrolytes, polyampholytes, hydrogels, and polymerizable surfactants. In Polymeric Surfactants, Surfactant Science Series. Vol. 42, New York Marcel Dekker, 1992 225-265. 

Fig. 7. Equilibrium water uptakes of chemically cross-linked polyampholyte hydrogel as a function of pH, compositions in mole fractions MAA/DMAEMA/ HEMA/EGDMA. Formulation A 10/10/79.5/0.5 (open squares). Formulation B 30/30/39.5/0.5 (open circles). Formulation C 49.75/49.75/0/0.5 (fitted circles)...

Chen, L., Tian, Z., and Du, Y. 2004. Synthesis and pH sensitivity of carboxymethyl chitosan-based polyampholyte hydrogels for protein carrier matrices. Biomaterials 25 3725-3732. 

Zhao, L., Mitomo, H., Yoshii, F. 2008c. Synthesis of pH-sensitive and biodegradable CM-ceUulose/chitosan polyampholytic hydrogels with electron beam irradiation. Journal of Bioactive and Compatible Polymers 23 319-333. 

Dogu, S., Kilic, M., Okay, O. (2009). Collapse of acrylamide-based polyampholyte hydrogels in water. Journal of Applied Polymer Science, 113, 1375-1382. 

Schroeder, M. E., Zurick, K. M., McGrath, D. E., Bernards, M. T. (2013). Multifunctional polyampholyte hydrogels with fouling resistance and protein conjugation capacity. Biomacromolecules, 14, 3112-3122. 

Polyampholyte hydrogels can be fabricated by utilizing hydrogen bond and Van der Waals forth. The self-assembly of peptides and proteins provide a method to control the gel structure and properties precisely [58-60]. 

Corpart and Candau [68, 69] described the formulation of polyampholytes containing both positive and negative charges in inverse microemulsions. The copolymers can show very different behaviors in the aqueous solution, ranging from insoluble, water-swollen hydrogels to water-soluble compounds, depending on the monomer composition. For polyampholytes with balanced stoichiometry, the polymer behavior is controlled by attractive electrostatic forces. The compound is usually insoluble in water, but becomes soluble upon the addition of salt. 

Sun, T.L. et ah. Physical hydrogels composed of polyampholytes demonstrate high toughness and viscoelasticity. Nature Materials, 2013. 12(10) 932-937. 

M.EA. Taleb, Radiation synthesis of polyampholytic and reversible pH-responsive hydrogel and its apphcation as drug delivery system. Polymer Bulletin, 61 (3), 341-351,2008. 

Xu, K., Wang, J., Chen, Q., Yue, Y, Zhang, W., Wang, P. (2008). Spontaneous volume transition of polyampholyte nanocomposite hydrogels based on pure electrostatic interaction. Journal of Colloid and Interface Science, 321, 272-278. 

Temperature and pH-sensitive hydrogels composed of polyampholyte CA and poly(NlPAAm] were successfully synthesized via free radical polymerization. The drug release of this hydrogel was determined with salicylic acid employed as the model drug. It found that the release of salicylic acid from the hydrogel particles was affected by temperature, pH, and the cross-linker content in the copolymer hydrogels (Cao et al., 2013). 

Cao ZF, Jin Y, Miao Q, Ma C-Y, Zhang B (2013). Preparation and properties of a dually responsive hydrogels based on polyampholyte for oral delivery of drugs. Polym Bull, 70,2675-2689. 

Cationic, anionic, and nonionic polyferrocenylsilane-based hydrogels were recently introduced [356-358]. In the case of anionic, permanently charged hydrogels, the electrochemical oxidation to ferrocenium imparts a polyampholytic behavior together with a color change. In addition, oxidation leads to shrinkage of the gel and to a loss of elasticity upon reduction, the former properties could be reached reversibly. 

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