Chain conformation of Poly [2-(methacryloyloxy) ethyltrimethylammonium chloride] in Aqueous Sodium Chloride Solutions
Chain conformation of Poly [2-(methacryloyloxy) ethyltrimethylammonium chloride] in Aqueous Sodium Chloride Solutions
复制标题
氯化钠水溶液中聚[2-(甲基丙烯酰氧基)乙基三甲基氯化铵]的链构象
DOI：
10.1021/ma4001868
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发表时间：
2013
期刊：
影响因子：
5.5
通讯作者：
Atsushi Takahara
中科院分区：
文献类型：
--
作者：
Talsuya Ishikawa;Moriya Kikuchi;Motoyasu Kobayashi;Atsushi Takahara
采用同步辐射小角X射线散射（SAXS）和动态光散射（DLS）方法，在298 K下对一系列重均分子量（Mw）为6.0 × 103 ~ 1.5 × 105的聚[2-（甲基丙烯酰氧基）乙基三甲基氯化铵]（PMTAC）在NaCl水溶液中的结构进行了表征。PMTAC的流体动力学半径（RH）随盐浓度（Cs）的增加而减小，在Cs = 0.5- 1.0M时趋于稳定。当分子量大于2 × 104 g/mol时，Z均均方根回转半径（Z_（？）S ~ 2）Z_（？）Z_（？）当分子量小于2 × 104 g/mol时，PMTAC分子链的构象随Cs的增加而增加，这可能是由于PMTAC分子链的局部构象发生了变化。为了研究PMTAC的局域链构象，采用具有弯曲能和扭转能的简单连续弹性丝模型，即螺旋蠕虫链（HW）模型，分析了PMTAC的散射函数和散射函数随分子量的变化. PMTAC的势能最小的HW模型的特征螺旋清楚地表明，本地构象的强烈影响的离子强度的解决方案。
A series of poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMTAC) in aqueous NaCl solutions with a weight-average molecular weight (Mw) of between 6.0 × 103and 1.5 × 105were characterized by synchrotron radiation small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS) measurements at 298 K. The hydrodynamic radius (RH) of PMTAC initially decreased with increasing salt concentration (Cs) and then leveled off atCs= 0.5–1.0 M. The values ofz-average root-mean-square radius of gyration (⟨S2⟩z1/2) simply increased with a decrease inCsforMw> 2 × 104g/mol. In contrast, the values of ⟨S2⟩z1/2forMw< 2 × 104g/mol increased with an increase inCsprobably because of a change in local conformation of PMTAC chain. To study local chain conformation of PMTAC, scattering functions andMwdependences of ⟨S2⟩z1/2andRHfor PMTAC were analyzed in terms of the helical wormlike chain (HW) model which is a simple continuous elastic wire model with bending and torsional energies. The characteristic helix of the HW model in potential energy minimum for PMTAC clearly indicates that the local conformation is strongly influenced by the ionic strength of the solution.