Amon the years, the combination between metal nanoparticles and polymers have gathered attention, specially when the polymer presents a behavior which changes with a specific stimulus. Poly(N-Isopropylacrylamide) (PNIPAM) for instance, is a temperature-responsive polymer which goes from hydrophilic to hydrophobic expulsing all its water content at around 32°C which is near the human body temperature; this property together with the innate properties of silver nanoparticles (e.g. thermal, high electrical and antimicrobial activity) poses an interesting option for a nanocomposite that can be used as drug carrier, tissue scaffold, and many other biomedical applications. In-situ synthesis performed by pulsed electrical discharges has barely been reported nor fully researched. Pulsed electrical discharges have the advantage of generating enough energy to affect the polymerization process and also the synthesis of the nanoparticles at the same time, hence reducing the reaction time and the utilization of additional chemicals. In this work, polymerization of nipam with minimum initiator concentration and synthesis of silver nanoparticles by the reduction of silver nitrate was tested with pulsed arc discharge. Results showed that both processes were successful obtaining PNIPAM and silver nanoparticles in the range of 150 to 320 nm. Moreover, in-situ synthesis of Ag@PNIPAM composite was performed by variating the ratio of nipam and silver nitrate solution, resulting in square shape nanoparticles with sizes in the range of 50 to 500 nm distributed in the polymer matrix and sphere shape nanoparticles in the range of 70 to 400 nm entangled in the polymer matrix. It is thought that by the variation of the solution ratio and discharge conditions (time and pulse repetition) the shape and size of the nanoparticles, and the polymer matrix could be controlled. These results show an appealing and novel synthesis process for nanomaterial composites with future biomedical applications.

In situ synthesis of Ag@PNIPAM composites by pulsed electric discharge and its future application to biomedicine

ACS Fall 2021

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