Self-Assembled Structures in Mixtures of Charged Amphiphiles and Particles

电话：9814398Dan NilyU。目前，两亲分子与固体颗粒的混合物形成的自组装结构被用于各种技术，如药物输送、涂料或介孔筛分。然而，虽然两亲性或胶体的相行为已经被广泛研究，但我们对混合体系的理解到目前为止还不完整。本研究的目的是得到两个一般的两亲性粒子体系的系统相图：(I)由不带电荷的疏水粒子与非离子两亲性粒子形成的聚集体，(Ii)带电胶体与相反带电的两亲性胶体的混合物。将建立一个相图模型，该模型将预测形成的聚集体的类型作为两亲性分子特征、粒子几何形状(球形或棒状)、粒子大小、不同组分的浓度的函数溶液的离子强度。两亲分子的标度和自洽场模型将与德拜-休克尔或泊松-玻尔兹曼方程和静电的蒙特卡罗模拟相结合。这种方法已经在几个初步研究中被发现是相当成功的(丹，生物物理。J，1996,1997，BiPhysica et Biochimica Acta，1998，Dan and Safran，BiPhys.将与特拉华大学的E.Kaler、宾夕法尼亚大学的D.Weitz和以色列海法IIT的Technion的Y.Talmon合作进行关于两亲粒子混合物的实验。这三个小组都专门研究复杂流体，特别是胶体和两亲分子的相行为。所使用的技术包括电子显微镜和冷冻电子显微镜、小角X射线散射和小角中子散射。理论和实验相结合的研究将使我们系统地了解控制非均相混合物中自组装的过程，即两亲和粒子。这样的理解对于能够实现特定性能参数的新材料的基本设计是至关重要的

ABSTRACTCTS-9814398Dan NilyU. of Delaware Self-assembled structures formed by mixtures of amphiphiles with solid particles are currently used in a variety of technologies such as drug delivery, paints or mesoporous sieves. Yet, while the phase behavior of either amphiphiles or colloids has been extensively investigated, our understanding of mixed system is, to date, incomplete.The aim of this study is to derive a systematic phase diagram of two general amphiphile-particle systems (i) Aggregates formed by uncharged, hydrophobic, particles with non-ionic ampphiphiles, and (ii) Mixtures of charged colloids wit oppositely charged amphiphiles.A model for the phase diagram will de developed which will predict the type of aggregate formed as a function of the amphiphile molecular characteristics, particle geometry (spherical or rod-like), particle size, the concentrations of the different components and, in that case systems, the solution ionic strength. Scaling and self-consistent field models for the amphiphiles will be combined with the Debye Hukel or Poisson-Boltzmann equation and Monte-Carlo simulations for the electrostatics. This approach has been found to be quite successful in several preliminary studies (Dan, Biophys. J., 1996, 1997, Biophysica et Biochimica Acta, 1998, Dan and Safran, Biophys. J. 1998).Experiments on model amphiphile-particle mixtures will be conducted in collaborations with E. Kaler of the University of Delaware, D. Weitz of the University of Pennsylvania, and Y. Talmon from the Technion, IIT in Haifa, Israel. All three groups specialize in the study of complex fluids in general, and the phase behavior of colloids and amphiphiles in particular. The techniques used include electron micrscopy and cryo-electron microscopy, small angle X-ray scattering and small angle neutron scattering.The combined theoretical and experimental studies will provide systematic understanding of the processes controlling self-assembly in heterogeneous mixtures, namely, amphiphiles and particles. Such an understanding is critical for the rationale design of new materials that can accomplish specific performance parameters