Nanoscale Interfacial Phenomena in Complex Fluids

Date :From 2008-05-19 To 2008-06-20
Advisory committee :
Local coordinators :Xiaosong Chen, Jixing Liu, Yuqiang Ma, Peng-Ye Wang, Haijun Zhou
International coordinators :Chun Liu,Tiezheng Qian, Ping Sheng, Xiao-Ping Wang,Hai-jun Zhou

Complex fluids refer to those fluids with molecular-scale microstructures whose interactions with the macroscopic flow can give rise to a variety of interesting and useful physical phenomena and properties. Examples of complex fluids include polymer solutions and melts, liquid crystals, gels, micellar solutions, membranes and vesicles, and electrorheological fluids. These materials often have great practical utilities since their microstructures can be designed and tuned to produce outstanding mechanical, optical and/or thermal characteristics.

The rich varieties of complex fluids lead to a diverse array of interfacial phenomena, e.g., structure and dynamics of thin films and surfaces of liquids, wetting and dewetting, friction at the fluid-solid interfaces, and self-assembly behavior. The interfacial dynamics tend to have a stronger influence on the overall flow behavior when the system size approaches nanoscale, whereby the large interface to volume ratio enhances the interfacial effects. Tremendous advantage can be gained in this interdisciplinary research area if researchers of different backgrounds are brought together, e.g., physicists, mathematicians, and chemical and mechanical engineers.

The present program intends to focus on the following four topics, with an emphasis on interfacial phenomena:

1. Onsager's principle of least energy dissipation (entropy production) and the least action principle in the hydrodynamic systems of soft matters. Applications and manifestations of these basic principles, together with specific kinematic transport properties, in soft matter systems, and in particular the application to interfacial phenomena, represent a new and exciting direction that not only can resolve classical problems (such as the moving contact line problem), but also offers a potential platform for understanding diverse phenomena within a unified framework.

2. Multi-scale modeling and simulations for soft condensed matters: The rheological and hydrodynamic properties of soft matters are often determined by their multi-scale nature, which presents a formidable challenge in modeling and simulations. In this program we intend to explore different existing methods/strategies in the fields, including molecular dynamics simulations, stochastic simulations, kinetic approaches, various mean-field approaches, different continuum descriptions (in terms of partial differential equations), as well as the coupling/interaction of information from differential scales/models.

3. Modeling, simulations and applications of micro- and nanofluidics: These include electro-kinetics and eletro-rheological fluids, Jeffery orbits, moving contact lines, wetting and spreading, and slip boundary conditions, etc. These topics are of imminent importance in terms of current developments in both experimental and theoretical studies, with potential applications in bio sensing, bio materials and other integrated bio systems.

4. Numerical algorithms and schemes for simulations of soft matters: The multi-scale and multi-physics nature of these materials requires sophisticated numerical methods in elasticity and fluid mechanics, quantum mechanics, stochastic process and other relevant physical processes. This topic is an integrate part of the research, underlying all previous 3 topics. Novel numerical developments provide concrete methods to verify and validate theoretical models and at the same time provide many of the feasible philosophy/methodology to the theoretical study. There will be a 3-day workshop focusing on the numerical algorithms.

Working program:

· Week 1: Opening Workshop
· Week 2: Topics 1 and 2
· Week 3: Topics 2 and 3
· Week 4: Topics 3 and 4
· Week 5: Topic 4

The first week of the proposed Program will be allocated to an opening workshop. After the Workshop in the first week, a new topic is to be opened every week (of the first four), and each topic is to be covered in two consecutive weeks. There will be a total of 50 to 60 hours of formal lectures and tutorials delivered by participants. (Each participant is expected to deliver at least one hour of formal lecture/tutorial, depending on the duration of his/her stay.) The opening week of workshop will have ~30 lectures. The remaining four weeks will have a total of 20-30 talks. Among these there will be 10-20 hours of tutorials for introduction to various research fields. They will be mostly arranged in the morning, typically 1 one-hour lectures/tutorials a day, making a total of 1x25=25 lectures/tutorials in the whole program after the first week. For this “formal” part of the program, the speaker, title, and abstract will be announced on a regular basis. There will also be numerous informal talks in the afternoon, flexible in both time and number. The participants will be encouraged to organize this “informal” part of the program, and the organizing committee members will act as initiators/moderators. .