A Study of Physical and Covalent Hydrogels Containing pH-Responsive Microgel Particles and Graphene Oxide

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• 作者：Zhengxing Cui ; Amir H. Milani ; Paula J. Greensmith ; Junfeng Yan ; Daman J. Adlam ; Judith A. Hoyland ; Ian A. Kinloch ; Anthony J. Freemont ; Brian R. Saunders
• 刊名：Langmuir
• 出版年：2014
• 出版时间：November 11, 2014
• 年：2014
• 卷：30
• 期：44
• 页码：13384-13393
• 全文大小：639K
• ISSN：1520-5827

文摘

In this study we mixed low concentrations of graphene oxide (GO) with microgel (MG) particles and formed composite doubly cross-linked microgels (DX MG/GO) gels. The MG particles comprised poly(ethyl acrylate-co-methacrylic acid-co-1,4-butanediol diacrylate) with pendant glycidyl methacrylate units. The MG/GO mixed dispersions formed physical gels of singly cross-linked MGs (termed SX MG/GO), which were subsequently heated to produce DX MG/GO gels by free-radical reaction. The influence of the GO concentration on the mechanical properties of the SX MG/GO and DX MG/GO gels was investigated using dynamic rheology and static compression measurements. The SX MG/GO physical gels were injectable and moldable. The moduli for the DX MG/GO gels increased by a factor of 4鈥? when only ca. 1.0 wt % of GO was included. The isostrain model was used to describe the variation of modulus with DX MG/GO composition. Inclusion of GO dramatically altered the stress dissipation and yielding mechanisms for the gels. GO acted as a high surface area, high modulus filler and played an increasing role in load distribution as the GO concentration increased. It is proposed that MG domains were dispersed within a percolated GO network. Comparison of the modulus data with those published for GO-free DX MGs showed that inclusion of GO provided an unprecedented rate of modulus increase with network volume fraction for this family of colloid gels. Furthermore, the DX MG/GO gels were biocompatible and the results imply that there may be future applications of these new systems as injectable load supporting gels for soft tissue repair.