Design and obtention of a novel polymeric nanomaterial with potential applications in diverse fields

S. BONGIOVANNI ABEL

Buenos Aires

Otro; Humboldt Colloquium ?Shaping the Future of German-Argentinian Scientific Cooperation ? The Role of Curiosity-Driven Research?; 2018

Alexander von Humboldt Fundation

Nanotechnology provides different tools and ways to synthesize and characterize novel materials. Previously, different sizes were explored (from the macroscopic to supramolecular level) to understand the properties of thermosensitive and conducting polymers and the synergistic effect of the combination in the same structure.1, 2 In the same way, a linear block copolymer (PNIPAM-b-PANI), containing a thermosensitive block (poly(N-isopropylacrylamide, PNIPAM) and a NIR light absorbing block (polyaniline, PANI) was now synthesized. The copolymer is soluble in aqueous and non-aqueous solvents, where PNIPAM is soluble, unlike PANI. Thin films of the copolymer are electrically conductive suggesting that the PANI blocks are electrically connected. If the PANI block absorbs NIR light, the produced heat should triggers the LCST of the PNIPAM block. Indeed, it is shown that the soluble polyaniline aggregate upon NIR light irradiation. The new nanomaterial is promising for some applications in diverse fields. On the one side, photothermal effect produced by the irradiation with near infrared light was tested, taking advantage of conducting polymers are capable to absorb light and generate localized heat that induce a collapse of the thermosensitive polymer. The increase in temperature of a PNIPAM-b-PANI copolymer aqueous solution was measured under NIR irradiation. The temperature increases with time when NIR irradiation is applied, reaching an increase of ~9 °C after 12 minutes. It is possible to think its application in antibacterial phothermal therapy.3 On another side, the resistivity value for the molecular nanocomposite was found to be of ca. 5.3 x 10-4 (Ω cm)-1. The result suggests that the PANI blocks are electrically connected in the solid state. The ability to sense the changes in the environment is promising for the application of the material in devices such as electronic noses using organic vapor compounds. Additionally, given the macromolecular nature of the material and its high solubility, it can be made into nanometric devices.4As a close-future perspective, the use of electrospinning techniques to generate nanofibrous polymeric mats employing this copolymer is proposed. In order to obtain uniform mats, different parameters need to be optimized such as applied voltage, tip-target distance, needle diameter, flow rate, etc. Electrospun mats will be characterized by FT-IR, thermogravimetric techniques, electronic microscopy, and others. The PNIPAM-b-PANI could be tried to cellular growth and sensors performance due to the PANI electrical capacity.1.Martínez, M.; Bongiovanni Abel, S.; Rivero, R.; Miras, M.; Rivarola, C.; Barbero, C. Polymer 2015, 78, 94-103.2.Bongiovanni Abel, S.; Molina, M. A.; Rivarola, C. R.; Kogan, M. J.; Barbero, C. A. Nanotechnology 2014, 25, (49), 495602.3.Bongiovanni Abel, S.; Yslas, E. I.; Rivarola, C. R.; Barbero, C. A. Nanotechnology 2018, 29, 125604.4. Bongiovanni Abel, S.; Olejnik, R.; Rivarola C.; Slobodian, P.; Saha, P; Acevedo D.; Barbero C. IEEE Sensors Journal 2018. In press. doi: 10.1109/JSEN.2018.2848843