Aniq Ahsan, Tristan Tsai Yuan Tan, Benny Kia Jia Chew, Siok Wei. Tay, Sze Yu Tan, Xu Jian Wei, Tzi Sum Andy Hor, Jia Min Chin. Institute of Materials ...
Light-Responsive Liquid Marbles and Dry Water Aniq Ahsan, Tristan Tsai Yuan Tan, Benny Kia Jia Chew, Siok Wei Tay, Sze Yu Tan, Xu Jian Wei, Tzi Sum Andy Hor, Jia Min Chin Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 3 Research Link, S117602. Singapore.
What are Liquid Marbles?
Light-Responsive Liquid Marbles
Liquid Marbles are liquid droplets encapsulated in a self-assembling, self-healing layer of micro or nano-scale hygrophobic (liquid repellent) particles1. Hygrophobic particles Substrate not wetted by liquid
Substrate wet by liquid
Figure 3. Liquid marble collapses when exposed to light, wetting the substrate. Encapsulated liquid
Substrate not wetted by Liquid Figure 1. Diagram of a liquid marble
What are Dry Water and Dry Liquids? A collection of micronized liquid marbles forms a powder-like, free flowing substance called a “Dry Liquid” which may be viewed as a liquid-in-air emulsion. When the encapsulated liquid is water, it is called “Dry Water”2.
Figure 4. Liquid marbles before(top) and after light source is switched on for about 5 minutes(bottom). Liquid marbles exposed to light collapse after about 5 minutes(right). Liquid marbles placed on aluminum foil are not exposed to light and do not collapse(left).
Light-Responsive Dry Water and Dry Matter Water droplets do not coalesce
Figure 2. Powder-like “dry water” consists of up to 95% water, more than seawater.
Water droplets coalesce
Substrate not wet by dry water
Substrate wet by liquid
Figure 5. Water droplets combine and wet substrate after exposure to light.
Conclusion and Potential applications: We have synthesized hydrophobic and oleophobic nanoparticles with photo-induced hygrophilicity. We then used these particles to form liquid marbles, dry water, dry ionic liquid and dry oil with photo-induced wettability. We are currently investigating such systems for photo-induced release of active materials for diverse applications.
References 1. P. Aussillous and D. Quere, Nature. 2001, 411, 924. 2. W. Wang, C. L. Bray, D. J. Adams and A. I. Cooper, J. Am. Chem. Soc. 2008, 130, 11608.
Acknowledgements The author gratefully acknowledges the support given by A*STAR (IMRE).