The work centers on using photonic force microscopy (PFM) to measure how effectively detergent removes dirt from fabric in a controlled environment. PFM is a novel technique: optical tweezers can trap nanometer- to micrometer-sized dielectric particles at the focal point of a laser and measure displacement forces of few pico-Newtons. In PFM both the force and displacement can be measured in liquid. This enables measurement, as during washing, of the detaching force of dirt particles with suitable dielectric properties.
The project is part of a wider collaboration including Unilever, Croda, NPL and the Technology Strategy Board worth over $2.08 million (£1.4 million). The goal is to design new detergents effective at lower temperatures, which will reduce energy and water consumption and the amount of detergent used, and ultimately reduce the negative impact of laundering on the environment.