28 January

Fast responsive photochromic materials through nanoemulsion entrapment

Tuesday 28 January 2020, 11:00am

Seminar Room of the Chemistry Department of UAB

PhD: Héctor Torres

Director: Dr. Claudio Roscini, Senior Postdoctoral Researcher at Nanostructured Functional Materials Group at ICN2.

Short Abstract: An optically transparent photochromic material with fast and liquid-like kinetic response has been developed, and the methodology to produce said material is described herein. This technology is based on the nanoemulsion entrapment (NEE) technique, in which a nanoemulsion is first formed and stabilized by a film-forming polymer, and then the solvent of the continuous phase is removed, to generate a film containing the emulsion droplets entrapped in it.

Having the photochromic dyes dissolved in the dispersed liquid phase of the droplets ensures minimal steric hindrance for the dye to isomerize and therefore the fastest photochromic kinetics for the dye used (i.e. liquid-like behavior), while the continuous polymeric film provides a solid platform, which is the most convenient for the majority of applications. Moreover, the NEE films are visually transparent (> 90 %T), since the dispersed droplets are reduced to the nanoscale size (< 100 nm), by either ultrasonic irradiation or high-pressure homogenization, minimizing light scattering.