Engineering physico-chemical interactions across drug delivery, agriculture and carbon capture

Abstract

The interface between two phases often limits the efficiency of several phenomena. In drug delivery, viscous formulations are difficult to inject through medical needles as the no-slip boundary condition between the needle and the viscous drug product greatly resists fluid flow. In agriculture, the inherent water repellency of plant surfaces causes pesticide sprays to bounce off, resulting in enormous waste and environmental pollution. In post-combustion carbon capture, absorbing gaseous CO₂ into liquids remains prohibitively expensive as reaction rates are limited by the low interfacial areas between the flue gas and absorbents in current systems. This work explores how introducing new interfaces or interfacial forces can help solve these three challenges. First, we demonstrate viscosity agnostic injectability of drug formulations through needles using core annular flows, where the transport of a highly viscous fluid through a needle is enabled via coaxial lubrication by a less viscous fluid. Second, by cloaking spray droplets in minute quantities of plant oils (≤ 1wt%), we enhance energy dissipation during droplet impact on hydrophobic surfaces and demonstrate a 5x reduction in pesticide waste on a variety of plant leaves. Finally, mist-scale droplets and space charge injection are used to enhance interfacial areas in CO2 absorption and develop a carbon capture system that could lead to a 2.6x reduction in plant capital costs.