Functional POSS based polyimide nanocomposite for enhanced structural, thermal, antifouling and antibacterial properties

Abstract

Polyhedral oligomeric silsesquioxane (POSS) molecules are a combination of organic and inorganic hybrid nanocage structures (1–3 nm), which makes them ideal building blocks for the fabrication of functional nanostructured filler, and modify physico-chemical properties of polymeric nanocomposites. Herein, silver nanoparticles functionalized POSS nanofillers were incorporated in poly(pyromellitic dianhydride-co-4,4̍-oxydianiline) amic acid (PAA) matrix by in-situ chemical method followed by imidization for the fabrication of polyimide (PI) nanocomposite. Significant improvement in structural, thermal and wettability properties of functional Ag-POSS-PI nanocomposites were observed due to electrostatic, Van der Waals and hydrogen bonding interactions of functional Ag-POSS nanofiller with –NH2 and –COOH groups of PAA. The hydrophilicity of Ag-POSS-PI film increased (contact angle 79 ± 1.5°) as compared with neat PI (103 ± 1.8°). The antibacterial response using Ag-POSS-PI nanocomposite film against the E. coli bacterial colonies tended to decline with 64 × 106 CFU/mL as compared with neat PI film (1 × 108 CFU/mL) which is attributed to the antibacterial action of Ag NPs and amine groups of octaammonium POSS in PI. As-synthesized functional POSS based PI nanocomposite potentially finds their applications in aerospace, fire retardancy, microelectronics, environmental and biomedical fields.