3-APTES on Dendritic Fibrous Mesoporous Silica Nanoparticles for the pH-Controlled Release of Corrosion Inhibitors

Abstract

Mesoporous silica nanoparticles (MSNPs) are currently used in different fields like catalysis, nanomedicine, and conservation science, taking advantage of their high surface area. Here, we synthesized and functionalized mesoporous dendritic fibrous nanoparticles to realize a smart delivery system of protective agents for metals. Different MSNPs were obtained via the microemulsion method followed by a hydrothermal or refluxing treatment at different w/o ratios, times, and temperatures. Dendritic spherical silica nanoparticles with specific features such as an appropriate size (450 nm), a very large surface area (600 m2 g−1), and a high yield synthesis (86%) were selected for surface modification. The fiber surface of the selected MSNPs was functionalized with 3-aminopropyl triethoxysilane (3-APTES). 3-APTES works as a pH-driven “nanogate”, suppressing the immediate leakage of the total guest molecule load and modulating the release as a function of pH conditions. Surface-modified MSNPs were tested as a reservoir of the most diffused corrosion inhibitors: Mercaptobenzothiazole (MBT) and 1H-Benzotriazole (BTA); their release properties were studied in solutions with pH = 4 and 7. Functionalized and non-functionalized MSNPs showed a good loading efficiency of guest molecules (34–64%) and a pH-dependent release of the corrosion inhibitors on a timescale of several hours.

In Vitro Viability Tests of New Ecofriendly Nanosystems Incorporating Essential Oils for Long-Lasting Conservation of Stone Artworks

“…For both systems, the lowest concentration (1 × 10 −6 M) fell below the detection instrumental limits, resulting in an artifact (dotted UV curve in Figure 3B,D). Using the protocol described in Section 4, dissolution profiles of both green biocides were obtained as concentration versus time (symbols in Figure 4) and a logarithmic fit was used to represent the kinetic curves (continuous curves in Figure 4) [68]. The OO and EU plots differed both in the quantity of released biocide and in the kinetics.…”

In Situ Evaluation of New Silica Nanosystems as Long-Lasting Methods to Prevent Stone Monument Biodeterioration

“…Furthermore, one technological advancement is the encapsulation of natural biocides in various nanostructures, such as silica nanoparticles or nanocapsules, for long-lasting reliability and selective activity [53][54][55][56][57]. These nanosystems offer controlled release mechanisms and provide an ecofriendly and sustainable approach to preserving cultural heritage [54].…”