Abstract:
The work presented here describes the development of controlled release and affordable mosquito repellent
bicomponent polymer filaments. These filaments may be used in the production of alternative malaria vector control
interventions aimed at reducing outdoor malaria transmission in resource-limited communities. The approach was to
develop a bicomponent polymer filament with a core containing the volatile repellent active and an outer membrane layer
that reduces the rate at which a volatile active is released to the atmosphere. The bicomponent filament was produced by a
simple melt extrusion and drawing process. The core polymer used was poly(ethylene-co-vinyl acetate) (EVA) and the
sheath polymer was high density polyethylene (HDPE). 40 wt.% N,N-Diethyl-m-toluamide (DEET) was incorporated into
the EVA via a simple absorption process at a temperature of approximately 81 °C. Scanning electron microscopy (SEM)
studies indicated that a bicomponent core-sheath structure was successfully formed by the melt extrusion and drawing
process. Raman studies showed that a concentration gradient developed across the bicomponent filament after the
manufacturing process. The Raman results suggest that the release of the repellent from the bicomponent filament is a
diffusion controlled process, a characteristic of controlled release. With these findings, the study should proceed to the
upscale of repellent impregnated bicomponent yarn production and fabric knitting. Such a fabric can be further studied for
effectivenes in reducing outdoor malaria transmission in laboratory and field trials.
