Hydroxyl radicals may be used as disinfection agent in the advanced oxidation processes or tertiary treatment of waste and occasionally drinking water. In this exploratory work, we wish to investigate the kinetics and mechanism of OH radicals with a gram-negative bacteria cell wall proxy. Neutron reflection will allow us to determine the site and mechanism OH attack, i.e. does the OH radical diffuse through the polysaccharide coat and destroy the lipid bilayer or does it repeatedly react with the polysaccharide coat. The kinetics of the oxidation and extent of the reaction will also be studied with neutron reflection. The proposal is a collaboration between two teams with expertise in gram-negative bacteria wall proxies and oxidation kinetics and supports a joint ISIS/DLS funded student.