当薄膜厚度接近分子链尺寸，纳米受限使分子链构象和缠结发生变化。正确理解受限高分子的链缠结有助于描述和预测纳米高分子材料的性能与流变行为，是发展高分子微纳米制造技术的重要理论基础。由于缺乏薄膜链缠结的表征方法，学术界尚未清晰认知薄膜受限高分子链缠结的变化及规律。液滴表面张力使黏弹态聚合物表面发生形变，产生润湿脊。我们前期研究发现，润湿脊高度随液滴作用时间出现一个恒定区域，称为润湿脊平台；并初步证实该平台的形成受分子链缠结控制。在此基础上，本项目提出从平台润湿脊高度出发，建立其与聚合物平台模量关系，进而研究薄膜缠结分子量的思路。项目将探索实现这一思路，建立相关方法，研究其在不同界面相互作用基底上的适用性，最终确立一种定量表征基底支撑聚合物薄膜链缠结的技术手段，明确适用范围，奠定理论基础。并将研究薄膜厚度、聚合物分子量、链结构等的影响，探索受限聚合物薄膜分子缠结、链构象变化的物理机制。

As film thickness approaches the molecular dimensions, polymer conformation and chains entanglements are expected to change significantly due to the spatial confinement. Achieving a deep understanding of the chains entanglements under nanoconfinement is definitely meaningful in realizing a better description and precise prediction of the rheological behavior of the nanoconfined polymers, and therefore is significant in the development of new nano-manufacturing technologies for polymer materials. However, due to the lack of reliable techniques characterizing the chain entanglement under confinement, the fundamental rules and mechanisms of the variation of chain entanglement upon confinement are far from understood. Consequently, there is a great demand for novel approaches based on various mechanisms to directly characterize the chain entanglements in the thin polymer film. When a sessile droplet is placed on a soft polymer surface, surface tension of droplets acting perpendicularly in the microscopic region of the three-phase line induces a local deformation on the surface of the materials, that is, a wetting ridge. Our preliminary studies showed that there exists a plateau region, called wetting ridge platform, in the plots of the height of wetting ridge against the droplet deposition time, and it was pre-confirmed that the platform was formed due to the chain entanglements in the polymer system. On the basis of this finding, the height of wetting ridge in the plateau region (hw0) was herein put forward as a key parameter to investigate the entanglement molecular weight of chains (Me) in thin polymer films. This project will explore such possibility and establish the method. We will investigate the quantitative relation between the hw0 and plateau modulus of the films, from which the Me can be derived, and meanwhile study the validity of the relation on films supported by substrates with various interfacial interactions with polymers to clarify where the method is applicable. Furthermore, the effect of film thickness, chemical structure and molecular weight of polymer chains will be investigated using this method and their associated mechanisms will be discussed as well. Results of this study could provide a new method measuring chain entanglement in the thin polymer film, as well as deepen our understanding of chain conformation and entanglement under geometrical confinement.