Müller Martin, Stühn Bernd, Busse Karsten, Kressler Jörg
Institute of Condensed Matter Physics, Technical University Darmstadt, D-64289 Darmstadt, Germany.
J Colloid Interface Sci. 2009 Jul 15;335(2):228-33. doi: 10.1016/j.jcis.2009.03.085. Epub 2009 Apr 8.
A w/o microemulsion consisting of n-decane, AOT, and water with a droplet volume fraction Phi=0.2 and a molar ratio of water to AOT omega=40 has been used as a model system to investigate the effect of added amphiphilic triblock copolymers on structure and conductivity of the system. Structure of the system is determined by small-angle X-ray scattering. Conductivity is measured in a wide frequency and temperature range. The pure microemulsion displays the known phenomenon of conductivity increase with temperature at the percolation temperature T(p). Droplets are found to decrease in size in the same temperature range. The triblock copolymer poly(perfluorohexylethyl methacrylate)-b-poly(ethylene oxide)-b-poly(perfluorohexylethyl methacrylate) has been added to the microemulsion such that the number of polymers per droplet z is between 0.5 and 2. The polymer dissolves in the microemulsion and is located in the droplet. Microemulsion droplets deform continuously from spherical to prolate ellipsoidal shape with increasing polymer content. Furthermore, a strong shift of T(p) to higher T with increasing polymer content is observed. For z > or = 1.5 DeltaT(p) is nearly constant. Besides the confinement effect the specific interaction of the polymer blocks with the surfactant layer are of importance.
一种由正癸烷、AOT和水组成的无油微乳液，其液滴体积分数Φ = 0.2，水与AOT的摩尔比ω = 40，已被用作模型系统来研究添加两亲性三嵌段共聚物对该系统结构和电导率的影响。该系统的结构由小角X射线散射确定。电导率在很宽的频率和温度范围内测量。纯微乳液在渗流温度T(p)下表现出电导率随温度升高的已知现象。发现在相同温度范围内液滴尺寸减小。已将三嵌段共聚物聚（甲基丙烯酸全氟己基乙酯）-b-聚（环氧乙烷）-b-聚（甲基丙烯酸全氟己基乙酯）添加到微乳液中，使得每个液滴的聚合物数量z在0.5到2之间。聚合物溶解在微乳液中并位于液滴内。随着聚合物含量的增加，微乳液液滴从球形连续变形为长椭球形。此外，观察到随着聚合物含量的增加，T(p)强烈向更高温度移动。对于z≥1.5，ΔT(p)几乎恒定。除了限制效应外，聚合物嵌段与表面活性剂层的特定相互作用也很重要。
