Adsorption of isothiazolinones onto mesoporous siliceous materials

M. SOLEDAD LEGNOVERDE; ELENA I. BASALDELLA

Madrid

Conferencia; 4th International Colloids Conference, Surface Design and Engineering; 2014

Isothiazolinones containing sulfur atom (S), nitrogen (N), oxygen (O) at 3 position and hydrogen (H) can find application for making broad-spectrum biocides and preservatives such as antiseptic agents, bactericides, slimicides, and fungicides. Isothiazolinone biocides have proven efficacy and performance in microbial control for various industrial applications. These biocides are effective at low concentrations, stable, and fast-acting in the inhibition of microbial growth and metabolism, aside from being capable of controlling biofilm development. The biggest application is in paint industry. Furthermore, recent studies about biocide encapsulations by adsorption onto   nanoporous inorganic materials indicate that this procedure could be appropriate for obtaining a longer-term protection from fungal attack to environmentally exposed paints.  The supported biocide could be released only on demand because adsorption interactions between the adsorbate molecules and the inorganic framework render the biocide less resistant to leaching. In this study, mesoporous silica materials are proposed as new hosts for stabilizing isothiazolinone-based biocides. We synthesized two types of porous matrices: SBA-15 silica and mesocellular siliceous foam (MCF). Pluronic and Pluronic/mesitylene mixtures were used as templates and tetraethoxysilane as silica source. The loading capacity of a mixture of methylisothiazolinone and chloromethylisothiazolinone on SBA-15 and MCF was investigated using UV-VIS spectroscopy. In order to have a better knowledge about the way the biocide molecules interact with the inorganic matrix, the biocide-loaded silica was studied by N2 adsorption, SEM and FTIR analysis. Isothiazolinone adsorption leads to a decrease in surface area and pore volume, indicating biocide adsorption inside the mesopores. SEM morphologies of material synthesized with and without biocide impregnation showed no changes. This study has shown that typical coating biocides can be encapsulated within mesoporous silica frameworks, preserving their original structure. The desorption process is currently under study.