CANADIAN: Shining a light on “NMR-invisible” biocidal borate glasses

Dissolvable copper-sodium-borate glass has found an industrial application as a wood preservative, where the biocidal copper and borate ions in solution slowly infiltrate and bind to wood’s chemical components, leading to an inhospitable environment for most microorganisms, tripling lifetimes of wood products (approx. ten years). The unique dissolution behaviour, which is paramount to the successful application of these glasses, is dependent on the copper-borate bonding in the glassy state: one cannot simply add the starting reagents to water and expect the same infiltration behaviour. The main goal is to understand the chemical bonding within the glass that results in the strong infiltration of the aqueous copper-borate complexes into the wood. Discernment of the different bonding environments in the glass is more reliable than in the solution state, and would aid future investigations of aqueous coordination complexes, likely by X-ray absorption. We will extract accurate information about the boron and copper bonding environments from neutron total scattering and x-ray total scattering, respectively (including dependence on independently measured oxidation state). In addition to fundamental understanding about copper in borates glass, we wish to quantitatively relate molecular structure to the macroscopic properties, such as dissolution behaviour, physical and mechanical properties.