Encapsulation of Functional Materials for Controllable Release

Abstract

Microparticles and microcapsules can encapsulate many important functional materials and release their contents when exposed to specific stimulus, such as temperature, osmotic pressure, magnetic field, light, mechanical force and pH value. Hence, encapsulation of functional materials attracts great interests from a variety of different areas including agriculture chemicals, food additives, petroleum additives, pharmaceuticals, cosmetic components and cells. We design and fabricate microparticles that rapidly release the encapsulated cargo upon contact with water. These microparticles can be used in biodiesel industry for targeted delivery of antimicrobial materials to water phase in biodiesel to prevent microbial contamination. We use polydimethylsiloxane (PDMS) microfluidic device to make water-in-oil single emulsion drops that contain model antimicrobial agent. Then we use UV light to polymerize the disperse phase to obtain microparticles. We demonstrate both short-term and long-term enhanced biocidal efficacy of microparticles in biodiesel. Among all the function materials, surface-active materials are very useful in many areas such as surfactants for enhanced oil recovery, while they are challenging to be encapsulated. We develop a new three-step bulk emulsification approach for high-throughput production of microcapsules encapsulating nonionic surface-active material for controllable release. We exploit the control of emulsification power and time of the three-step bulk emulsification to control the mean size and standard deviation of the droplets. We demonstrate that the microcapsules can release the nonionic surface-active upon in contact with acid. Based on this strategy, other surface-active agent can be encapsulated to expedite a wide range of applications such as oil recovery and daily chemistry.