Flexible-templated imprinting for fluorine-free, omniphobic plastics with re-entrant structures
Document Type
Article
Publication Date
3-1-2021
Abstract
HYPOTHESIS: Compared to vertical micro-pillars, re-entrant micro-structures exhibited superior omniphobicity for suspending liquids to Cassie-Baxter state. However, the existing re-entrant structures rely on complex multi-step deposition and etching procedures. The conventional, rigid-templated imprinting would instead damage the re-entrant structures. This leads to the question: is it possible to preserve the re-entrant curvatures by a flexible-templated imprinting? EXPERIMENTS: We facilely imprinted the re-entrant structures on a plastic substrate using a flexible nylon-mesh template. The effect of imprinting time (15-35 min), temperature (110-120 °C) and pressure (15-50 Bar) was investigated. To further improve the liquid-repellency and abrasion resistance, the silica nanoparticles (30-650 nm) along with epoxy resin binder (10 mg/mL) were pre-coated. FINDINGS: A one-step imprinting is sufficient to fabricate the re-entrant structures by utilizing flexible nylon-mesh template, without damaging the imprinted structures after the demolding process. The pre-coated silica nanoparticles and epoxy resin (1) improved liquid repellency by introducing hierarchical surface structures (e.g. contact angle hysteresis of olive oil reduced > 10°), and (2) acted as a protective layer against mechanical abrasion (omniphobicity maintained after 25 cycles, ~1.6 kPa sand paper abrasion). Additionally, the fluorine-free post-treatment was sufficient for the omniphobicity on the obtained plastic structures.
Publication Source (Journal or Book title)
Journal of colloid and interface science
First Page
668
Last Page
675
Recommended Citation
Zhao, X., Park, D. S., Choi, J., Park, S., Soper, S. A., & Murphy, M. C. (2021). Flexible-templated imprinting for fluorine-free, omniphobic plastics with re-entrant structures. Journal of colloid and interface science, 585, 668-675. https://doi.org/10.1016/j.jcis.2020.10.046