Controllable hydrophilic/superhydrophobic patterned coatings for optical information encryption/decryption based on water-triggered opaque to translucent transition

Xiaojing Su; Kunquan Li; Huali Xie; Zhuohan Chen; Xuanjun Li; Wenjian Wu

doi:10.1016/j.jcis.2023.10.093

Controllable hydrophilic/superhydrophobic patterned coatings for optical information encryption/decryption based on water-triggered opaque to translucent transition

J Colloid Interface Sci. 2024 Jan 15;654(Pt A):764-773. doi: 10.1016/j.jcis.2023.10.093. Epub 2023 Oct 19.

Authors

Xiaojing Su¹, Kunquan Li², Huali Xie², Zhuohan Chen², Xuanjun Li², Wenjian Wu³

Affiliations

¹ School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523808, China. Electronic address: suxj@dgut.edu.cn.
² School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523808, China.
³ School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523808, China. Electronic address: wuwj@dgut.edu.cn.

PMID: 37866048
DOI: 10.1016/j.jcis.2023.10.093

Abstract

Anti-counterfeiting technologies are crucial for securing the authenticity and proof of commodities, in which the optical information encryption/decryption has attracted extensive attention for its overriding advantages of visibility and convenience. Inspired by the unique transparency transformation phenomenon of Diphylleia grayi petals, a controllable hydrophilic/superhydrophobic patterned coating with water-triggered opaque to translucent transition is proposed through the construction of a superhydrophobic coating, subsequent air plasma etching under a mask, and final hydrophilic modification to introduce stable invisible patterns. The superhydrophobic region exhibits great water repellency with a water contact angle (WCA) at 157°, while the hydrophilic region quickly absorbs water with a WCA at 61°. The patterned coating presents an opaque state for the serious light scattering induced by the rough microstructure and large refractive index difference between the coating and air, while the hydrophilic patterns on the coating transform to translucent after water infiltration for the reduced roughness and close refractive indexes of the coating and water. The information revealing is rapid and reversible, and demonstrates heat and long-term stability and great reusability. The findings conceivably stand out as a new methodology to fabricate controllable superwettable coatings with optical information encryption/decryption capability for application in anti-counterfeiting.

Keywords: Encryption/decryption; Hydrophilic/superhydrophobic patterns; Optical information; Transparency transition; Water-triggered.