Effect of gelatin molecular charge heterogeneity on formation of intermolecular complexes and coacervation transition
Effect of gelatin molecular charge heterogeneity on formation of intermolecular complexes and coacervation transition
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DOI：
10.1002/polb.21120
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发表时间：
2007-07-01
影响因子：
--
通讯作者：
Bandyopadhyay, S.
中科院分区：
文献类型：
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作者：
Mohanty, B.;Gupta, Amarnath;Bandyopadhyay, S.
我们通过测量Zeta电位分布来研究明胶分子在等电点pH=5(PI)和PHS=p1+/-1时的分子电荷不均匀。探讨了它对非溶剂乙醇诱导形成可溶性分子间络合物的影响。发现在pH=5时，电荷分布是对称的，当分子表现出聚两性电解质(PA)行为时，小净电荷(接近于零)的存在有利于结合的开始和可溶络合物的形成。这些分布在pH为6时变得不对称，但出现了复杂的形成和凝聚。另一方面，对于pH为4的样品，这些分布是强烈不对称的，分子具有很高的净正电荷，这样的体系不会产生凝聚。结合电泳法、浊度法、原子力显微镜和纳米压痕研究的实验结果，讨论了PA到聚电解质的转变及其对凝聚的影响。(C)2007年威利期刊公司。
We investigate the molecular charge heterogeneity of gelatin molecules at three different pHs: isoelectric pH = 5 (pI), and at pHs = p1 +/- 1 by measuring the zeta potential distributions. Its effect on the formation of soluble intermolecular complexes induced by the presence of a nonsolvent, ethanol, was explored. The charge distributions were found to be symmetric at pH = 5, where the onset of binding, and formation of soluble complexes were observed to be facilitated by the presence of a small net charge (close to zero) with the molecules exhibiting polyampholyte (PA) behavior. These distributions turned asymmetric at pH 6, yet complex formation and coacervation occurred. On the other hand, for pH 4 samples, these distributions were found to be strongly asymmetric with the molecules possessing very high net positive charge, such a system did not yield coacervation. The PA to polyelectrolyte transition and its repercussion on coacervation has been discussed in the light of the experimental results obtained from electrophoresis, turbidimetry, atomic force microscopy, and nanoindentation studies. (c) 2007 Wiley Periodicals, Inc.