Multifunctional Polypyrrole-silver Coated Layered Double Hydroxides Embedded into a Biodegradable Polymer Matrix for Enhanced Antibacterial and Gas Barrier Properties

In this study, polypyrrole-silver coated layered double hydroxides (LDHs@PPy-Ag) was prepared by chemical polymerization of pyrrole (Py) with silver ions. Silver nanoparticles (AgNPs) could be uniformly reduced onto PPy coatings in situ by redox reaction during simultaneous polymerization process. And LDHs@PPy-Ag/poly(ε-caprolactone) (PCL) nanocomposites were fabricated by solution casting method. It is revealed that spherical AgNPs are loaded on PPy coatings uniformly. Particularly, compared with pure PCL, LDHs@PPy-Ag/PCL nanocomposites with incorporation of only 1 wt% LDHs@PPy-Ag show a 17% increase in tensile strength (36.5 MPa) and a 29% increase in elongation at break (822%). Upon PPy-Ag coatings onto original LDHs, oxygen relative permeability of LDHs@PPy-Ag/PCL nanocomposites decreases to 52% with the same addition. Meanwhile, due to the double antibacterial activity of PPy and AgNPs, the antibacterial rate of LDHs@PPy-Ag reaches 100%. And the corresponding LDHs@PPy-Ag/PCL nanocomposites also show outstanding antibacterial activity. Considering the superiority of their comprehensive performance, antibacterial LDHs@PPy-Ag/PCL nanocomposites can be used further for the application as biodegradable polymeric active packaging materials.