Photoactuated Droplet Microfluidics

A system of Photoactuated Droplet Microfluidics (PDM), in which a droplet of fluid is moved by way of the manipulation of the wettability of a spiropyran functionalized surface via irradiation with ultraviolet and visible light, was proposed. The photochromic behaviors of several species of spiropyran were studied and a procedure was prepared for testing the photochromism of spiropyran species synthesized in lab. Two methods were proposed to optimize the surface area of spiropyran functionalized polymer available to a droplet in the PDM system. The first method was the physical modification of PMMA to created posted structures through the use of a laser machining and hot embossing process. The second method involved the construction and optimization of an electrospinner, which was used to create PMMA nanofibers functionalized with spiropyran. The following describes the successful proof of photoswitchable wettability in the physically modified chips, and photochromism in the electrospun nanofibers, and describes the significance of these findings towards the development of a PDM system.