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

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-4,4-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 AgPOSS-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 x 10(6) CFU/mL as compared with neat PI film (1 x 10(8) 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.