Achieving Stable Patterns in Multicomponent Polymer Thin Films Using Marangoni and van der Waals Forces

Saurabh Shenvi Usgaonkar, Christopher J. Ellison, Satish Kumar

Research output: Contribution to journalArticlepeer-review

Abstract

Liquid-air interfaces can be deformed by surface-tension gradients to create topography, a phenomenon useful for polymer film patterning. A recently developed method creates these gradients by photochemically patterning a solid polymer film. Heating the film to the liquid state leads to flow driven by the patterned surface-tension gradients, but capillary leveling and diffusion of surface-active species facilitate eventual dissipation of the topography. However, experiments demonstrate that using blends of high- and low-molar-mass polymers can considerably delay the decay in topography. To gain insight into this observation, we develop a model based on lubrication theory that yields coupled nonlinear partial differential equations describing how the film height and species concentrations evolve with time and space. Incorporation of a nonmonotonic disjoining pressure is found to significantly increase the lifetime of topographical features, making the model predictions qualitatively consistent with experiments. A parametric study reveals the key variables controlling the kinetics of film deformation and provides guidelines for photochemically induced Marangoni patterning of polymer films.

Original languageEnglish (US)
Pages (from-to)6660-6672
Number of pages13
JournalLangmuir
Volume37
Issue number22
DOIs
StatePublished - Jun 8 2021

Bibliographical note

Funding Information:
This work was supported through the Industrial Partnership for Research in Interfacial and Materials Engineering at the University of Minnesota. S.S.U. acknowledges partial support through a fellowship awarded by the PPG Foundation.

Publisher Copyright:
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PubMed: MeSH publication types

  • Journal Article

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