3 years ago

Photoresponsive Sponge-Like Coating for On-Demand Liquid Release

Photoresponsive Sponge-Like Coating for On-Demand Liquid Release
Dirk J. Broer, Kevin H. J. Leunissen, Albert P. H. J. Schenning, Dirk J. Mulder, Anne Helene Gelebart, Danqing Liu, Jop van Gerven
Many publications report on stimuli responsive coatings, but only a few on the controlled release of species in order to change the coating surface properties. A sponge-like coating that is able to release and absorb a liquid upon exposure to light has been developed. The morphology of the porous coating is controlled by the smectic liquid crystal properties of the monomer mixture prior to its polymerization, and homeotropic order is found to give the largest contraction. The fast release of the liquid can be induced by a macroscopic contraction of the coating caused by a trans to cis conversion of a copolymerized azobenzene moiety. The liquid secretion can be localized by local light exposure or by creating a surface relief. The uptake of liquid proceeds by stimulating the back reaction of the azo compound by exposure at higher wavelength or by thermal relaxation. The surface forces of the sponge-like coating in contact with an opposing surface can be controlled by light-induced capillary bridging revealing that the controlled release of liquid gives access to tunable adhesion. A photosponge consisting of a porous liquid crystal network with smectic molecular order, crosslinked with an azobenzene molecule is reported. The pores are filled with liquid cyanobiphenyl. UV light irradiation shrinks the network, resulting in liquid secretion by the coating, while visible-light irradiation triggers reabsorption of the liquid. The coating regulates by light-induced adhesion and friction at its surface.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/adfm.201705942

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.