MilliporeSigma

Nature-inspired robust hydrochromic film for dual anticounterfeiting.

iScience (2021-06-24)
Pengxiang Si, Mingrui Liang, Manyou Sun, Boxin Zhao
ABSTRACT

Nature-inspired materials have been actively developed for anticounterfeiting applications. Among a variety of stimuli-responsive anticounterfeiting strategies, hydrochromic materials exhibit reversible color change in response to moisture or water and have the advantage of being easy to authenticate. However, the security level of current hydrochromic anticounterfeiting materials is not sufficient for practical applications since they only exhibit a single anticounterfeiting function, where the information switches between visible and invisible. To improve the security level and efficiency of hydrochromic anticounterfeiting materials, here we developed a robust dual hydrochromic material via the self-assembly of polyurethane (PU)-polyelectrolytes colloids with which the desired information can not only switch between visible and invisible but also transform from one pattern to another within 3 s without the need of any external instruments. The bio-inspiration, material design and demonstrated hydrochromic properties might have profound implications for using colloidal complexes to make advanced anticounterfeiting materials.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Polyethylenimine, branched, average Mw ~25,000 by LS, average Mn ~10,000 by GPC, branched
Sigma-Aldrich
2,2-Bis(hydroxymethyl)propionic acid, 98%
Sigma-Aldrich
Ammonium hydroxide solution, ACS reagent, 28.0-30.0% NH3 basis