title: Photoresponsive liquid marbles and dry water.
abstract: Stimuli-responsive liquid marbles for controlled release typically rely on organic moieties that require lengthy syntheses. We report herein a facile, one-step synthesis of hydrophobic and oleophobic TiO2 nanoparticles that display photoresponsive wettability. Water liquid marbles stabilized by these photoresponsive TiO2 particles were found to be stable when shielded from ultraviolet (UV) radiation; however, they quickly collapsed after being irradiated with 302 nm UV light. Oil- and organic-solvent-based liquid marbles could also be fabricated using oleophobic TiO2 nanoparticles and show similar UV-induced collapse. Finally, we demonstrated the formation of the micronized form of water liquid marbles, also known as dry water, by homogenization of the TiO2 nanoparticles with water. The TiO2 dry water displayed a similar photoresponse, whereby the micronized liquid marbles collapsed after irradiation and the dry water turned from a free-flowing powder to a paste. Hence, by exploiting the photoresponsive wettability of TiO2, we fabricated liquid marbles and dry water that display photoresponse and studied the conditions required for their collapse.
authors.affiliation: Institute of Materials Research and Engineering , 3 Research Link, Singapore 117602, Singapore.
authors.forename: Tristan Tsai Yuan
authors.initials: TT
authors.lastname: Tan
authors.forename: Aniq
authors.initials: A
authors.lastname: Ahsan
authors.forename: Michael R
authors.initials: MR
authors.lastname: Reithofer
authors.forename: Siok Wei
authors.initials: SW
authors.lastname: Tay
authors.forename: Sze Yu
authors.initials: SY
authors.lastname: Tan
authors.forename: Tzi Sum Andy
authors.initials: TS
authors.lastname: Hor
authors.forename: Jia Min
authors.initials: JM
authors.lastname: Chin
authors.forename: Benny Kia Jia
authors.initials: BK
authors.lastname: Chew
authors.forename: Xiaobai
authors.initials: X
authors.lastname: Wang
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D053758:Nanoparticles / Q000737:chemistry; D009821:Oils / Q000737:chemistry; D010316:Particle Size; D055668:Photochemical Processes; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*; D017155:Wettability
chemical_list: D009821:Oils; D012997:Solvents; D014867:Water; C009495:titanium dioxide; D014025:Titanium