Modeling of stimulated hydrogel volume changes in photonic crystal Pb2+ sensing materials
Modeling of stimulated hydrogel volume changes in photonic crystal Pb2+ sensing materials
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DOI：
10.1021/ja051456p
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发表时间：
2005-08-03
影响因子：
15
通讯作者：
Asher, SA
中科院分区：
文献类型：
--
作者：
Goponenko, AV;Asher, SA
我们模拟了一种结合Pb2+并用作光子晶体化学传感材料的材料的受激水凝胶体积跃迁。该材料由含有冠醚分子识别基团的聚合结晶胶体阵列（PCCA）水凝胶组成。PCCA是一种聚丙烯酰胺水凝胶，它嵌入了一个类似于100纳米的单分散聚苯乙烯球体的晶体胶体阵列（CCA）。设置阵列间距以衍射可见光谱区域中的光。Pb2+结合引起的水凝胶体积变化改变了阵列间距并改变了衍射波长。该系统使我们能够灵敏地跟踪由于冠醚螯合基团固定Pb2+而导致的水凝胶膨胀行为。Pb2+的结合使其反离子固定。这就产生了唐南电位，从而产生渗透压，使水凝胶膨胀。我们在此继续基于Flory的凝胶膨胀理论开发水凝胶膨胀的预测模型。我们能够定性地模拟PCCA膨胀，但不能正确地模拟在最低Pb2+浓度下观察到的大响应性，这导致实验观察到Pb2+的低检测限。这些PCCA材料使受激水凝胶体积转变得以研究。
We modeled the stimulated hydrogel volume transitions of a material which binds Pb2+ and is used as a photonic crystal chemical sensing material. This material consists of a polymerized crystalline colloidal array (PCCA) hydrogel which contains a crown ether molecular recognition group. The PCCA is a polyacrylamide hydrogel which embeds a crystalline colloidal array (CCA) of monodisperse polystyrene spheres of similar to 100 nm. The array spacing is set to diffract light in the visible spectral region. Changes in the hydrogel volume induced by Pb2+ binding alter the array spacing and shift the diffracted wavelength. This system allows us to sensitively follow the hydrogel swelling behavior which results from the immobilization of the Pb2+ by the crown ether chelating groups. Binding of the Pb2+ immobilizes its counterions. This results in a Donnan potential, which results in an osmotic pressure which swells the hydrogel. We continue here our development of a predictive model for hydrogel swelling based on Flory's theory of gel swelling. We are qualitatively able to model the PCCA swelling but cannot correctly model the large responsivity observed at the lowest Pb2+ concentrations which give rise to the experimentally observed low detection limits for Pb2+. These PCCA materials enable stimulated hydrogel volume transitions to be studied.