Preparation And Applications Of Hydrophilic Polymers Functionalized Polypyrrole/graphene Oxide Nanocomposites

Graphene composite materials,especially Graphene/Polymer Composites have attracted people's attention because it can strengthen the property and even product new characters.Among those Graphene/Polymer Composites,polypyrrole/graphene oxide(PPy/GO)nanocomposites have excellent mechanical property,high conductivity,high specific capacitance,high specific surface area and good biocompatibility.Therefore,it was wildly used on lots of fields such as supercapacitor,neural probe and biogalvanic battery.But PPy/GO cannot disperse well in water so that its applies in electrochemical biosensor and catalytic have been restricted.In order to improve its dispersibility in water,hydrophilic polymer could be modified on the surface of PPy/GO nanocomposites due to its plentiful hydrophilic groups.In this paper,we have chosen three common hydrophilic polymers(HP),polyacrylamide(PAM),polyacrylic acid(PAA)and polyvinyl pyrrolidone(PVP)functionalized PPy/GO nanosheets and combine them in covalent bonding by simple polymerization process,respectively.In this method,their dispersibility improved at a large extent that can be used as electrode material for electrochemical biosensor,then we use them modified glassy carbon electrodes(GCEs)to test their electrocatalytic activity in simultaneously dopamine(DA)and ascorbic acid(AA).As a result,only PAM/PPy/GO nanosheets and PAA/ PPy/GO nanosheets modified GCEs can exhibited good electrochemical responses to distinguish DA from AA in their mixture at certain concentrations.Particularly,PAM/PPy/GO modified GCEs have lower detection limit for DA and AA,its numerical value is 0.408 ?M and 0.659 ?M,respectively.Therefor,PAM/PPy/GO nanosheets modified GCEs can act as a good electrochemical sensor with high sensitivity and selectivity for detect DA and AA.In addition,High-density and well-dispersed Ag nanoparticles(Ag NPs)with a mean size of 20 nm have been successfully supported on the surface of polyacrylamide functionalized polypyrrole/graphene oxide(PAM/PPy/GO)nanosheets.The obtained Ag/PAM/PPy/GO composite nanosheets exhibited the excellent catalytic activity for reduction of 4-nitrophenol by NaBH4 with the kinetic reaction rate constant of 3.38×10-2/s due to the synergistic effect of all the components of the composite nanosheets.The corresponding catalytic mechanism has been revealed by investigating the effect of different components of Ag/PAM/PPy/GO composite nanosheets on the catalytic performance: GO with the excellent two-dimensional structures offered the large surface area for more Ag NPs loading;PPy with the high electric conductivity promoted the electron transport rate in reduction of 4-NP;PAM not only acted as a good linker between Ag NPs and PPy/GO nanosheets for the synthesis of Ag/PAM/PPy/GO composite nanosheets,but also facilitated the efficient contact between 4-NP and Ag NPs;Ag NPs were the catalytic active site for the reduction of 4-NP,respectively.Therefore,Ag/PAM/PPy/GO composite nanosheets can act as excellent stabilized and efficient catalysts to provide a new choose for the reduction of 4-NP.