Events

Soft dendritic microparticles with unusual adhesion and structuring properties

Simeon Stoyanov / Unilever

Date: Wednesday 9 October 2019 13:00 - 14:00

Location: Engineering Building, SEMS Seminar Room

For the start of the Engineering Seminar Series - from the Chemical, Aero, and Mechanical Engineering divisions it is our pleasure to welcome

Prof. Simeon Stoyanov, Lead Scientist at Unilever R&D, as well as
Visiting Professor at UCL, University of Wageningen, and North Carolina State University

Abstract:
The interplay between morphology, excluded volume, and adhesivity of particles critically determines the physical properties of numerous soft materials and coatings. Branched particles or nanofibers, nanofibrillated cellulose, or fumed silica can enhance the structure-building abilities of colloids, whose adhesion may also be increased by capillarity or binding agents6. Nonetheless, alternative mechanisms of strong adhesion found in nature involve fibrillar mats with numerous subcontacts (“contact splitting”) as seen in the feet of gecko lizards and spider webs. In this talk, we describe the fabrication of hierarchically structured polymeric microparticles having branched nanofiber coronas with a dendritic morphology. Polymer precipitation in highly turbulent flow results in microparticles with fractal branching and nanofibrillar contact splitting that exhibit gelation at very low volume fractions, strong inter-particle adhesion and binding into coatings and nonwoven sheets. These soft dendritic particles also have potential advantages for food, personal care or pharmaceutical product formulations.