Developing Optical Tweezers, Spectroscopy and Microfluidics to Investigate High Volume Consumer Products

As the use of consumer products grows, quality control becomes a more and more important aspect. In this thesis, three different high volume consumer products are investigated through the use of optical instrumentation; these are hair dye, dishwasher detergent and clothes detergent. A bespoke Raman tweezer system was built around microfluidic channels to investigate the reactions which occurin a dishwasher via flowing solutions past a trapped species made from acrylic, a common problem item in dishwashers. It was found that it is possible to predict some of the reaction processes via this method, although the particle build-up can lead to some instabilities in the system. An absorbance spectrometer system was also built around microfluidic channels to investigate the reactions which develop the colour of hair dye, to advance a current method by Proctor and Gamble. Another spectrometer system built to study the reflection and transmission of light by stained fabric was developed to quantify the performance of fabric detergents.