FUNCTIONALIZATION OF THE POLISYLOXAN GEL WITH SILVER NANOPARTICLES AND ITS CHARACTERIZATION

Abstract

In the present investigation we present a polysiloxane composite functionalized with silver nanoparticles (NPs-Ag). NPs-Ag was synthesized, by reduction of a silver nitrate solution (AgNO3) with sodium borohydride (NaBH4), the NPs-Ag were characterized by the UVvisible spectrophotometric method, finding that between 400 - 410 nm the typical peak of NPs-Ag by surface plasmon resonance. In the Dynamic Light Scattering (DLS) analysis of the NPs-Ag, a polydisperse distribution was found with two populations of 59.78 nm in 70% and 4.33 nm in 30%. Subsequently, the polysiloxane gel was synthesized by hydrolyzing chlorosilane, using diethyl ether as the solvent, the obtained polysiloxane was characterized by infrared Fourier transform spectrophotometry (FTIR). In the spectrum peaks are observed in the region of 1258.88 cm-1 corresponding to methyl, between 1000 - 1100 cm-1 a peak corresponding to the Si-O-Si bond and a band at 792.10 cm-1 characteristic of the siloxanes, confirming the presence of the polysiloxane. The polysiloxane (PS) gel was functionalized with NPs-Ag, obtaining a milky yellow gel, due to the resonance absorption of the surface plasmons. DLS analysis of the PS-NPs-Ag gel showed a monodisperse distribution with an average size of 158.7 nm at 100%, because the gel includes NPs-Ag in its structure. The PS-NPs-Ag gel was characterized by FTIR, observing a peak between 1000 and 1100 cm-1 corresponding to Si-O-Si and a band at 803.33 cm-1 typical of siloxanes, as well as a band absorption at 3384 cm-1 corresponding to NPs-Ag. In the thermogravimetric analysis (TGA) of the PS-NPs-Ag gel it is shown that at the temperature of 374.96 °C it reaches the melting point, characteristic of a polysiloxane and at 630.22 °C the sample decomposes. Using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), a silver concentration of 5.2 ppm was found. SEM-EDX shows the typical morphology of the PS-NPs-Ag gel, and a signal corresponding to the presence of silver is also observed.