MoO3 Nanobelts Embedded Polypyrrole/SIS Copolymer Blends for Improved Electro- Mechanical Dual Applications

Abstract

In past, polymers were well known for their insulating nature and the phenomenon of conduction in polymers were considered a marvel. But with the discovery of conducting polymers (CPs), this concept has been obsoleted which paved new ways to use polymers for a variety of applications such as sensors, light weight batteries, solar cells, transistors, anti-static coatings, compact capacitors and electromagnetic shielding for various devices etc. Polypyrrole (PPy) received special interest as compared to other conducting polymers because of its biocompatibility, cost efficiency, excellent environmental stability along with tunable electrical conductivity. However, PPy reveals poor thermal properties, insolubility due to cross linking of PPy chains, lack of mechanical and film forming properties due to very rigid structure that limits its usage and large scale production. In this research work, the aforementioned limitations of polypyrrole has been tried to overcome by making their blends with a thermoplastic poly styrene-isoprene-styrene (SIS) triblock copolymer that gave high mechanical strength and film forming capabilities to the polypyrrole while the uniformly dispersed polypyrrole has enhanced the electrical conductivity of the insulating copolymer. FTIR analysis of blends confirmed the incorporation of PPy in SIS copolymer. Mechanical properties of these blends were studied by tensile testing and electrical properties by four-probe conductivity method. Enhancement of mechanical and electrical properties of blends was reported up to 15 w/w % of PPy/SIS blends. Mechanical properties and electrical conductivity of 15 w/w % of blends was further enhanced by incorporating MoO3 nanobelts in these blends as nanofiller. These nanobelts were synthesized by ecofriendly hydrothermal synthesis method using ammonium molybdate as a precursor. Their synthesis was confirmed by XRD, SEM and EDS analysis. In order to enhance the mechanical strength and electrical conductivity of blends, 15 w/w % of PPy/SIS blends were loaded with 1-4 w/w % of nanobelts to form polymeric composites. Enhancement of the aforementioned properties were recorded up to 3 w/w % of MoO3 loading into PPy-SIS nanocomposites while beyond this value MoO3 has shown agglomeration instead of uniform dispersion in film.