Abstract

Ultrathin shelled capsules and responsive microfibers via non-confined microfluidics

Ankur Chaurasia, Student, King's College London

Conventional microfluidic encapsulation technologies, where the core droplets are first formed and then encapsulated downstream in the shell phase, lack dexterity in controlling the shape, size, location and orientation of the encapsulated core droplets inside the shell phase. For example, in case of a double emulsion, such a drop formation technique usually leads to the formation of drops containing multiple cores, which suffers from a reduced control over the rate of release of core contents. Similarly, in the case of oil-loaded alginate fibers, the conventional encapsulation approach limits the manipulation of droplets to locate them at desired places within the fibers. In this talk, I will describe how a simple modification to the encapsulation technique, which enables the droplet formation and encapsulation to occur simultaneously, can completely override the formation of multi-core droplets by forming unified core-shell capsules with tunable shell thickness. I will also discuss that by taking the simultaneous form-and-encapsulate approach, the location and orientation of the core droplets inside fibers can be precisely tuned, which can transform a passive oil-loaded microfiber into a responsive microfiber that is able to release its core via a stimulation such as dehydration. The proposed device for fabricating these tailored polymeric materials offers several conveniences due to a quiescent outer phase, such as buoyancy-driven transportation, and facile scale up due to its non-confined geometry.