Raman and ATR FT-IR investigations of innovative silica nanocontaniers loaded with a biocide for stone conservation treatments

TL;DR

This study uses Raman and ATR FT-IR spectroscopy to analyze silica nanocontainers loaded with a biocide, revealing how their geometry affects biocide loading and release for stone conservation.

Contribution

It provides new insights into the loading mechanisms and interactions of biocides within silica nanocontainers using combined spectroscopic techniques.

Findings

Nanocontainer geometry influences biocide loading and release.

Biocide interacts with surfactant and tends to dimerize.

Spectroscopic techniques reveal physical and chemical loading mechanisms.

Abstract

In the last years, significant research efforts have been devoted to the reduction of environmental impact of biocides and to the improvement of their effectiveness over time against degradation of stone artifacts. This work reports the spectroscopic characterization of two silica nanosystems, with different geometry and structure, loaded with a biologically-active compound, the 2-mercaptobenzothizole (MBT), for controlled antifouling release on the surface of outdoor stone artefacts. We have combined FT-IR spectroscopy in ATR mode and Raman spectroscopy to investigate the biocide loading mechanism in both nanosystems from the physical and chemical point of view. These techniques demonstrate that the geometry of confinement influences the loading of the nanoparticles and their interaction with the confining medium, with possible consequences in the biocide release rate. Moreover we have seen that the biocide interacts with the surfactant (cetrimonium bromide, CTAB) and tends to dimerize.