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Mechanically Switchable Wetting Petal Effect in Self-Patterned Nanocolumnar Films on Poly(dimethylsiloxane)

Authors :
Julian Parra-Barranco
Carmen Lopez-Santos
Juan R. Sánchez-Valencia
Ana Borras
Agustin R. Gonzalez-Elipe
Angel Barranco
Source :
Nanomaterials, Vol 11, Iss 10, p 2566 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

Switchable mechanically induced changes in the wetting behavior of surfaces are of paramount importance for advanced microfluidic, self-cleaning and biomedical applications. In this work we show that the well-known polydimethylsiloxane (PDMS) elastomer develops self-patterning when it is coated with nanostructured TiO2 films prepared by physical vapor deposition at glancing angles and subsequently subjected to a mechanical deformation. Thus, unlike the disordered wrinkled surfaces typically created by deformation of the bare elastomer, well-ordered and aligned micro-scaled grooves form on TiO2/PDMS after the first post-deposition bending or stretching event. These regularly patterned surfaces can be reversibly modified by mechanical deformation, thereby inducing a switchable and reversible wetting petal effect and the sliding of liquid droplets. When performed in a dynamic way, this mechanical actuation produces a unique capacity of liquid droplets (water and diiodomethane) transport and tweezing, this latter through their selective capture and release depending on their volume and chemical characteristics. Scanning electron and atomic force microscopy studies of the strained samples showed that a dual-scale roughness, a parallel alignment of patterned grooves and their reversible widening upon deformation, are critical factors controlling this singular sliding behavior and the possibility to tailor their response by the appropriate manufacturing of surface structures.

Details

Language :
English
ISSN :
20794991
Volume :
11
Issue :
10
Database :
Directory of Open Access Journals
Journal :
Nanomaterials
Publication Type :
Academic Journal
Accession number :
edsdoj.63c86fbddd3c42c3acb9197a434129c7
Document Type :
article
Full Text :
https://doi.org/10.3390/nano11102566