Pattern formation in dynamic self-assembly systems

• Applicant: Professorin Dr. Svetlana Gurevich
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 332704749

• Final Report Year: 2022

Final Report Abstract

Surface patterning is an important part of modern technology, including the applications in electronics, information processing and storage, biodetection as well as nano- and microfluidics. Among the various patterning techniques, the concepts of self-assembly and self-organization pave a way to realize micro-features over large areas via a so-called bottom-up approach, in which the microscopic structures spontaneously assemble based on nonlinear interactions molecules or nanoparticles. In this project we focused on the so-called dip-coating surface patterning technique. There, a substrate is coated by dipping it into a trough which is filled with the complex fluid that has to be applied to the substrate. Depending on the experimental conditions, various periodic and branched patterns can be created using this technique. A special case of dip-coating is the Langmuir-Blodgett (LB) transfer. Here, a trough filled with water is used, on which a floating surfactant layer is prepared. A substrate is then pulled out of the trough, leading to a transfer of the floating monolayer onto the substrate. The Langmuir-Blodgett technique is usually used for transferring films or ordered two-dimensional structures of organic species formed at the air-water interface and was also successfully applied to influence the phase transitions of long-chain surfactant monolayers, effectively forming patterns at the three-phase contact line during the transfer. The objective of this project is to develop effective theoretical models and strategies to control the behavior and dynamics of pattern formation in dip-coating and Langmuir-Blodgett transfer experiments, where solutions or suspensions are transferred onto a solid substrate producing patterned deposit layers.

Publications

• Dip-coating with prestructured substrates: transfer of simple liquids and Langmuir–Blodgett monolayers. J. Phys. Condens. Matter, 29(1):014002, (2017)
  M. Wilczek, J. Zhu, L. Chi, U. Thiele, and S. V. Gurevich
  
• Sliding drops – ensemble statistics from single drop bifurcations. Phys. Rev. Lett., 119:204501, (2017)
  M. Wilczek, W. Tewes, S. Engelnkemper, S.V. Gurevich, and U. Thiele
  
• Continuation for Thin Film Hydrodynamics and Related Scalar Problems, 459–501. Springer International Publishing, Cham, (2019)
  S. Engelnkemper, S. V. Gurevich, H. Uecker, D. Wetzel, and U. Thiele
  
• Effects of time-periodic forcing in a Cahn-Hilliard model for Langmuir- Blodgett transfer. Phys. Rev. E, 99:062212, (2019)
  P.-M. T. Ly, U. Thiele, L. Chi, and S. V. Gurevich
  
• Self-organized dip-coating patterns of simple, partially wetting, nonvolatile liquids. Phys. Rev. Fluids, 4:123903, (2019)
  W. Tewes, M. Wilczek, S. V. Gurevich, and Uwe Thiele
  
• Two-dimensional patterns in dip coating - first steps on the continuation path. Physica D, 409:132485, (2020)
  P.-M. T. Ly, K. D. J. Mitas, U. Thiele, and S. V. Gurevich