Ou Kangkang, Dong Xia, Qin Chengling, Ji Xinan, He Jinxin
College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China.
College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China; Key Laboratory of Textile Science & Technology, Ministry of Education, Shanghai 201620, China.
Mater Sci Eng C Mater Biol Appl. 2017 Aug 1;77:1017-1026. doi: 10.1016/j.msec.2017.03.287. Epub 2017 Mar 31.
It is well known that preparation method of hydrogels has a significant effect on their properties. In this paper, freeze-thawing and anneal-swelling were applied to prepare poly(vinyl alcohol)/polyacrylamide (PVA/PAM) double-network hydrogels with covalently and physically cross-linked networks. The properties of these hydrogels were investigated and compared to control hydrogels. Results indicated that hydrogels fabricated by freeze-thawing show larger pores size and higher swelling capacity than those made by anneal-swelling and control hydrogels. Hydrogels prepared by anneal-swelling exhibit higher mechanical strength, energy dissipation, fracture energy, gel fraction and crystallinity than those made by freeze-thawing and control hydrogels. Physical cross-linking plays a key role in formation of physical-chemical double-network. The toughening mechanism of double-network hydrogel is related to their chain-fracture behavior and elasticity. The results also indicated that appropriate methods can endow hydrogels with specific microstructures and properties which would broaden current hydrogels research and applications in biomedical fields.
众所周知，水凝胶的制备方法对其性能有显著影响。本文采用冻融法和退火溶胀法制备了具有共价和物理交联网络的聚乙烯醇/聚丙烯酰胺（PVA/PAM）双网络水凝胶。对这些水凝胶的性能进行了研究，并与对照水凝胶进行了比较。结果表明，冻融法制备的水凝胶比退火溶胀法制备的水凝胶和对照水凝胶具有更大的孔径和更高的溶胀能力。退火溶胀法制备的水凝胶比冻融法制备的水凝胶和对照水凝胶具有更高的机械强度、能量耗散、断裂能、凝胶分数和结晶度。物理交联在物理化学双网络的形成中起关键作用。双网络水凝胶的增韧机制与其链断裂行为和弹性有关。结果还表明，适当的方法可以赋予水凝胶特定的微观结构和性能，这将拓宽当前水凝胶在生物医学领域的研究和应用。
