Bending moduli of microemulsions; comparison of results from small angle neutron scattering and neutron spin-echo spectroscopy
Bending moduli of microemulsions; comparison of results from small angle neutron scattering and neutron spin-echo spectroscopy
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DOI：
10.1088/0953-8984/17/31/017
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发表时间：
2005-08-10
影响因子：
2.7
通讯作者：
Richter, D
中科院分区：
文献类型：
--
作者：
Monkenbusch, M;Holderer, O;Richter, D
由水、油和表面活性剂组成的双连续微乳液的性质在很大程度上取决于含有油水界面的表面活性剂的弯曲模数。在以C(I)E(J)为表面活性剂的体系中，可以通过添加两嵌段共聚物(增压效应)和均聚物(反向增压效应)或两者的组合来改变这些模数。用小角中子散射(SANS)和中子自旋回波谱(NSE)研究了均聚物(PEP(X)和PEO(X)，X=5和10 kg/m o l)的加入对表面活性剂层结构、弯曲模数和动力学的影响。除了提供有关微乳液结构的信息外，中子散射还是一种可以用来测量局部弯曲模数K的微观探测器。聚合物的加入使一系列相应的微乳液的K值发生变化。我们将SANS的分析结果与NSE实验的结果联系起来。弯曲模数的比较揭示了NSE和SANS的不同重整化长度尺度。如果观察到重整化性质，SANS和NSE导出的K值的比较得到了一致的图像。最后给出了一种将NSE数据转换为K的可靠数值的现成方法。
The properties of bicontinuous microemulsions, consisting of water, oil and a surfactant, depend to a large extent on the bending moduli of the surfactant containing oil-water interface. In systems with C(i)E(j) as surfactant these moduli can be modified by the addition of diblock copolymers (boosting effect) and homopolymers (inverse boosting effect) or a combination of both. The influence of the addition of homopolymers (PEP(X) and PEO(X), X = 5 or 10 kg/mol molecular weight) on the structure, bending modulus and dynamics of the surfactant layer is studied with small angle neutron scattering (SANS) and neutron spin-echo spectroscopy (NSE). Besides providing information on the microemulsion structure, neutron scattering is a microscopic probe that can be used to measure the local bending modulus K. The polymer addition gives access to a homologous series of microemulsions with changing K values. We relate the results obtained by analysis of SANS to those from NSE experiments. Comparison of the bending moduli obtained sheds light on the different renormalization length scales for NSE and SANS. Comparison of SANS and NSE derived K values yields a consistent picture if renormalization properties are observed. Finally a ready to use method for converting NSE data into reliable values for K is presented.