title: Decreasing the Wettability of Cellulose Nanocrystal Surfaces Using Wrinkle-Based Alignment.
abstract: Cellulose nanocrystals (CNCs) are a particularly appealing format of the natural biopolymer due to their exceptional strength, nanoscale dimensions, and needle-like shape anisotropy. However, CNCs are hydrophilic and hence their wettability makes them impractical for many coating applications, with various approaches using chemical functionalization to overcome this. Here we show that CNC-coated surfaces can be rendered hydrophobic by alignment of the native CNCs using a wrinkled template-mediated printing process. We present a novel and simple method allowing full release of the CNCs from the template and their permanent adsorption into fine patterns onto the surface, thus preventing CNC repositioning during wetting. The aligned CNCs induce strong pinning effects that capture and retain water droplets with high contact angle and large roll-off angles, without becoming susceptible to oil contamination. The fabrication process for these coatings could be achieved by large-scale printing, making them a practical and cost-effective solution to hydrophobic coatings from raw cellulosic materials.
authors.affiliation: School of Chemistry, Monash University , Clayton, Victoria 3800, Australia.
authors.forename: Ragesh
authors.initials: R
authors.lastname: Prathapan
authors.affiliation: Department of Chemical and Biomolecular Engineering and the Particulate Fluids Processing Centre, University of Melbourne , Parkville, Victoria 3010, Australia.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Berry
authors.affiliation: Institute for Physical Chemistry and Polymer Physics, Leibniz-Institut für Polymerforschung Dresden e.V. , 01069 Dresden, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Fery
authors.affiliation: Bioresources Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University , Clayton, Victoria 3800, Australia.
authors.forename: Gil
authors.initials: G
authors.lastname: Garnier
authors.affiliation: School of Chemistry, Monash University , Clayton, Victoria 3800, Australia.
authors.forename: Rico F
authors.identifier: http://orcid.org/0000-0003-2926-0095
authors.initials: RF
authors.lastname: Tabor
keywords: alignment; cellulose nanocrystals; hydrophobicity; pinning; wettability