title: Synthesis, characterization, and multilayer assembly of pH sensitive graphene-polymer nanocomposites.
abstract: pH sensitive graphene-polymer composites have been prepared by the modification of graphene basal planes with pyrene-terminated poly(2-N,N'-(dimethyl amino ethyl acrylate) (PDMAEA) and poly(acrylic acid) (PAA) via pi-pi stacking. The pyrene-terminal PDMAEA and PAA were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization with a pyrene-functional RAFT agent. The graphene-polymer composites were found to demonstrate phase transfer behavior between aqueous and organic media at different pH values. Atomic force microscopy (AFM) analysis revealed that the thicknesses of the graphene-polymer sheets were approximately 3.0 nm when prepared using PDMAEA (M(n): 6800 and PDI: 1.12). The surface coverage of polymer chains on the graphene basal plane was calculated to be 5.3 x 10(-11) mol cm(-2) for PDMAEA and 1.3 x 10(-10) mol cm(-2) for PAA. The graphene-polymer composites were successfully characterized using X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and thermogravimetric analysis (TGA). Self-assembly of the two oppositely charged graphene-polymer composites afforded layer-by-layer (LbL) structures as evidenced by high-resolution scanning electron microscopy (SEM) and quartz crystal microbalance (QCM) measurements.
authors.affiliation: Centre for Advanced Macromolecular Design, School of Chemical Sciences and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Jingquan
authors.initials: J
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Tao
authors.forename: Wenrong
authors.initials: W
authors.lastname: Yang
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.forename: Cyrille
authors.initials: C
authors.lastname: Boyer
authors.forename: Richard
authors.initials: R
authors.lastname: Wuhrer
authors.forename: Filip
authors.initials: F
authors.lastname: Braet
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Davis