Rapid fiber diameter measurement in aqueous solutions with OFDA 2000

In this paper, a new technique has been developed to enable fiber diameters to be measured in an aqueous environment using the OFDA 2000 instrument. The existing OFDA instrument has only been used to measure diameters of animal fibers under dry conditions. This new technique was utilized to assess the effects of pH and temperature on the diameters of merino wool fibers in aqueous environments. Significant changes in fiber diameter under aqueous conditions were found as a function of pH and temperature. Wool fiber diameters were at a minimum close to the wool isoelectric point (pH 4.8) and increased at both lower and higher pHs. Swelling of merino wool fibers was observed to increase linearly by around 15% as the temperature rose from ambient to 70°C.