Hydrophobic surface patterning with soft, wax-infused micro-stamps

Soroosh Torabi, Zhuoyun Cai, Jonathan T. Pham, Christine A. Trinkle

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Hypothesis: Waxy hydrocarbons diffuse freely in polydimethylsiloxane (PDMS), and this capability can be leveraged to generate inexpensive surface micropatterns that modify adhesion and wetting. Experiments: Patterns are created by placing a waxy Parafilm sheet on the back of a PDMS stamp containing microscale surface features. When heated, the paraffin liquefies and diffuses through the stamp, creating a thin liquid layer on the micropatterned stamp surface; when placed in contact with a target surface, the layer solidifies and is retained on the target when the stamp is removed. Micropatterns were generated on different materials and surface topographies; pattern geometry was evaluated using optical profilometry and changes in wetting were evaluated using contact angle goniometry. Diffusion of paraffin through PDMS was evaluated using XPS. Findings: Wax micropatterns have submicron lateral resolution and thickness ranging from 85 to 380 nm depending on contact time. By using XPS analysis to track paraffin diffusion within the PDMS stamp during this process, we estimate the diffusion coefficient to be 5.3 × 10−7 cm2/s at 65 °C. This means that the paraffin layer at the stamp surface replenishes in less than a second after stamping, so it can be used multiple times without re-inking to deposit complex, multi-layer paraffin patterns.

Original languageEnglish
Pages (from-to)494-500
Number of pages7
JournalJournal of Colloid and Interface Science
Volume615
DOIs
StatePublished - Jun 2022

Bibliographical note

Publisher Copyright:
© 2022 Elsevier Inc.

Keywords

  • Hydrophobic patterning
  • Microcontact printing
  • Paraffin diffusion
  • Polydimethylsiloxane (PDMS) stamp

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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