Conformations and Dynamics of Polymers at Interfaces

9316157拉法洛维奇最近，几个研究小组证明，由于将长聚合物分子限制在界面上会产生很大的熵，为简单液体开发的经典润湿理论不适用。为了更好地了解聚合物薄膜的润湿特性，我们采用了多种辅助技术(SIMS、反射率、透射电子显微镜和原子力显微镜)来进行一个三重计划。1)液体聚合物薄膜的润湿特性：我们正在探索链尺寸对薄膜稳定性、表面扩散、玻璃化转变、粗糙表面的润湿和总密度的影响。包括新的实验现象在内的平均场理论的修正正在发展中。2)末端官能化聚合物的表面改性：在稳态剪切作用下，末端接枝聚合物在熔体和溶液中的构象正在被研究。对电刷的面内结构进行了研究，并与理论模拟进行了比较。3)三嵌段共聚物的表面诱导有序化：三嵌段共聚物具有形成表面诱导胶束凝胶膜的独特能力。我们正在研究均聚物膜在这些凝胶表面上的渗透和润湿，作为两个组分的相对分子质量和与有序表面的相互作用能的函数。众所周知，超薄的聚合物薄膜具有广泛的应用，如润滑剂、光学和电子元件的涂层以及粘合剂。为了使这些薄膜有效，它们必须湿润它们所涂布的表面或通过界面渗透以提供粘合强度。***

9316157 Rafailovich Recently, several research groups have demonstrated that due to the large entropy associated with confining long polymer molecules at interfaces, the classical wetting theories developed for simple liquids do not apply. I order to obtain a better understanding of the wetting properties of polymer films we are employing a variety of complementary techniques (SIMS, reflectivity, TEM, and AFM) to conduct an three-fold program. 1) Wetting properties of thin liquid polymer films: We are exploring the role of the chain dimensions on the film stability, surface diffusion, glass transition, wetting of rough surfaces, and total density. Modification of mean-field theories to include new experimental phenomena are being developed. 2) Surface modification via end- functionalized polymers: The conformations of end-grafted polymers are being studied both in melts and solutions under steady-state shear. The in-plane structure of brushes is being studied and compared with theoretical simulations. 3) Surface induced ordering of triblock copolymers: Triblock copolymers have the unique ability to form surface-induced micelle gel films. We are studying the penetration and wetting of homopolymer films on these gel surfaces as a function of the relative molecular weights of the two components and the interaction energies with the ordering surface. Very thin polymer films are known to have a large variety of applications such as lubricants, coatings for optical and electronic components, and adhesives. In order for these films to be effective, they must wet the surfaces upon which they are spread or penetrate through the interfaces to provide adhesive strength. ***