State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, PR China.
J Colloid Interface Sci. 2011 Jan 15;353(2):498-505. doi: 10.1016/j.jcis.2010.10.002. Epub 2010 Oct 8.
Polyacrylic acid (PAA) and polyacrylamide (PAAm) double network (DN) hydrogels with high mechanical strength (about 1.5 MPa) are obtained when two kinds of monomer solutions of 4M AA with 5 mol% crosslinker and 4M AAm with 0.1 mol% crosslinker are used for the optimal preparation. Their high mechanical strength can be maintained even at high water content (above 50%) and at external stimuli (solvent and pH). This optimized DN hydrogel is used to develop the PAA/PAAm inverse opal hydrogel with DN structure by twice infiltration-polymerization and colloidal templating. Its photonic stop band can be tuned by controlling the solvent and pH. It first shows a small red-shift (about 20 nm), and then a large blue-shift (about 180 nm) with the increased ethanol content. For pH response, the DN inverse opal hydrogel has a large stop-band shift of about 140 nm when the pH increases from 1.2 to 5.6. Moreover, the DN inverse opal hydrogel also shows rapid recovery ability without hysteresis phenomenon in strong acidic environment, good reproducibility and durability. The interaction between the independently crosslinked PAA network and PAAm network plays a significant role in determining the response performance.
当使用两种单体溶液，即 4M AA（含 5 mol%交联剂）和 4M AAm（含 0.1 mol%交联剂）来进行最佳制备时，可得到力学强度高（约 1.5 MPa）的聚丙烯酸（PAA）和聚丙烯酰胺（PAAm）双重网络（DN）水凝胶。即使在高含水量（高于 50%）和外部刺激（溶剂和 pH 值）下，它们的高机械强度也能得以保持。该优化后的 DN 水凝胶通过两次浸渗聚合和胶体模板化被用于开发具有 DN 结构的 PAA/PAAm 反蛋白石水凝胶。通过控制溶剂和 pH 值，可以调节其光子带隙。随着乙醇含量的增加，它首先显示出小的红移（约 20nm），然后显示出大的蓝移（约 180nm）。对于 pH 值响应，当 pH 值从 1.2 增加到 5.6 时，DN 反蛋白石水凝胶的带隙位移约为 140nm。此外，DN 反蛋白石水凝胶在强酸性环境中还表现出快速恢复能力，无滞后现象，具有良好的重现性和耐用性。独立交联的 PAA 网络和 PAAm 网络之间的相互作用对确定响应性能起着重要作用。
