Facile preparation of silver-based nanocomposites via thiol-methacrylate ?click? photopolymerization

SILVANA V. ASMUSSEN; CLAUDIA I. VALLO

EUROPEAN POLYMER JOURNAL

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2016 vol. 79 p. 163 - 175

0014-3057

Dispersions of silver nanoparticles (Ag NPs) in a tetrafunctional thiol were prepared byin situ reduction of silver nitrate with 2,6-di-tert-butyl-para-cresol. The obtained Ag NPs,were maintained in a stable colloidal state for more than eleven months at ambient temperature.The thiol monomer acts as both stabilizing agent and reactive solvent. Mixturesof dispersions of Ag NPs in thiol and a bifunctional methacrylate monomer were photoactivated with 2,2-Dimethoxy-2-phenylacetophenone (DMPA) or Camphorquinone (CQ) and then photopolymerized by irradiation with UV or visible light respectively. Dispersions containing high amounts of Ag NPs were more efficiently photopolymerized with the pair CQ/visible light. This is attributed to fact that the emission range of the UV LED (365 ± 5 nm) was overlapped with the surface plasmon resonance band of the Ag NPs(k < 400 nm). Conversely, there was no overlap between the surface plasmon resonanceband of the Ag NPs and the emission range of the visible LED (peak at 470 nm).Consequently, most of the visible light was absorbed by CQ, while a fraction of the UV light was absorbed by the Ag NPs and was not available for the photoinitiation process.The thiol-methacrylate matrix of the nanocomposites was characterized by measuringthe glass transition temperature, the flexural modulus and the compressive strength. Thelow toxicity of the reactants used in the synthesis in combination with antimicrobialactivity of Ag NPs makes the nanocomposite materials synthesized in this study veryattractive for the preparation of biomaterials and coating with improved biocompatibility.