Kim Hyong-Jun, Deng Jianjun, Lalli Jennifer Hoyt, Riffle Judy S, Viers Brent D, Esker Alan R
Department of Chemistry and the Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
Langmuir. 2005 Mar 1;21(5):1908-16. doi: 10.1021/la0475674.
Mixtures of a polyhedral oligomeric silsesquioxane, trisilanolisobutyl-POSS, and a polar silicone, poly(dimethyl-co-methylvinyl-co-methyl, 2-diphenyl phosphine oxide ethyl) siloxane (PDMS-PO), spread as Langmuir monolayers at the air/water interface are used to examine the surface phase behavior and aggregation of trisilanolisobutyl-POSS as a function of silicone composition. Analyses of the surface pressure-area per monomer (Pi-A) isotherms in terms of the collapse pressures and excess Gibbs free energies of mixing indicate the monolayers form slightly negative deviation mixtures. Direct observations of surface morphology with Brewster angle microscopy in the collapsed regime reveal that the governing factor for aggregation is the collapse Pi of the component with a stronger affinity for water. In trisilanolisobutyl-POSS/PDMS-PO blends, POSS aggregates as discrete domains and does not coalesce into larger aggregates or networklike structures for <80 wt % POSS, a feature that is vastly different from a previous study of POSS blended with regular poly(dimethylsiloxane).
由多面体低聚倍半硅氧烷、三硅醇异丁基-POSS和极性硅氧烷聚（二甲基-共-甲基乙烯基-共-甲基，2-二苯基氧化膦乙基）硅氧烷（PDMS-PO）组成的混合物，以朗缪尔单分子层的形式在空气/水界面铺展，用于研究三硅醇异丁基-POSS的表面相行为和聚集情况与硅氧烷组成的关系。根据崩塌压力和混合过量吉布斯自由能对每个单体的表面压力-面积（π-A）等温线进行分析，结果表明单分子层形成略微负偏差混合物。在崩塌状态下用布鲁斯特角显微镜对表面形态进行直接观察发现，聚集的主导因素是对水亲和力较强的组分的崩塌π值。在三硅醇异丁基-POSS/PDMS-PO共混物中，对于小于80 wt%的POSS，POSS以离散域的形式聚集，不会聚集成更大的聚集体或网络状结构，这一特征与之前对POSS与常规聚二甲基硅氧烷共混的研究有很大不同。
