Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
ACS Appl Mater Interfaces. 2010 May;2(5):1499-504. doi: 10.1021/am100130n.
We prepared a poly(vinyl alcohol) (PVA) gelated crystalline colloidal array (GCCA) through physical cross-linking. PVA hydrogel was formed by utilizing a chilling-thawing method while the CCA was physically immobilized within the PVA hydrogel matrix. After being chilled at 2 degrees C for 24 h, the gel could be formed without disturbing the CCA. With the repetition of chilling-thawing cycle, the hydrogel network was reinforced. This photonic crystal material could be shaped as needed and efficiently diffracts visible light, and the diffraction wavelength can be tuned anywhere within the visible spectrum by simply varying the CCA concentration. The GCCA represents sol-gel reversibility as the temperature is cycled. It has been observed that the GCCA retained its ability of diffraction after rehydration, and the sample could be stored for long periods of time. We further functionalized the PVA hydrogel with Chitosan (CS), and the pH sensing behavior of the PVA/CS GCCA was observed. It revealed that the sensitivity of the PVA/CS GCCA correlates with the CS concentration.
我们通过物理交联的方法制备了聚（聚乙烯醇）（PVA）凝胶结晶胶体阵列（GCCA）。利用冷却-解冻方法形成 PVA 水凝胶，而 CCA 则物理固定在 PVA 水凝胶基质中。在 2°C 下冷却 24 小时后，无需干扰 CCA 即可形成凝胶。通过重复冷却-解冻循环，水凝胶网络得到增强。这种光子晶体材料可以按需成型，并有效地衍射可见光，通过简单地改变 CCA 浓度，可以在可见光谱的任意位置调节衍射波长。GCCA 代表溶胶-凝胶的可逆性，因为温度是循环的。已经观察到 GCCA 在重新水合后保留了其衍射能力，并且可以长时间储存该样品。我们进一步用壳聚糖（CS）功能化 PVA 水凝胶，并观察了 PVA/CS GCCA 的 pH 传感行为。结果表明，PVA/CS GCCA 的灵敏度与 CS 浓度相关。
