Study Of The Electrochemical Sensors Based On The Two Block Polymer Composites

For the moment, the composites prepared by electrostrostaic adsorption assembly, physical encapsulating, metal deposition, calcination, etc., have been applied to modifying the electrodes in the field of electrochemical sensor. Block polymer aroused much attention in electrochemical modified electrodes, although the synthesis of block copolymers is not difficult. However the applications to electrochemical sensors of the block copolymer are rare, especially block copolymer compound material. In this paper, the electrochemical properties of the block polymer (noted as PHEMA-b-PDMAEMA) that synthesized by a hydrophilic neutral block(PHEMA)and cationic weak polyelectrolyte block(PDMAEMA) are studied. We use the block copolymer composite materials to modify electrodes, and study block polymer composite materials in the application of electrochemical sensors. The main work of this paper is summarized as follows:(1) Preparation of PHEMA-b-PDMAEMA/glucose oxidase/graphene composites modified electrode and its electrocatalysis toward glucose (Glu) and hydrogen peroxide (H2O2). Positively charged diblock copolymer(PHEMA-b-PDMAEMA) combined the negatively charged glucose oxidase (GOD) to composite films respectively by electrostatic attraction, and then utilized good conductivity graphene(rGO) to modify electrodes, which are used to study the electrocatalytic activity of the enzymes. Electrochemistry behaviors and surface morphology of the PHEMA-b-PDMAEMA/GOD/rGOs composite films are characterized by cyclic voltammetry(CV), electrochemical impedance spectroscopy (EIS), current time curves(i-T), square wave voltammetry(SWV) and scanning electron microscope (SEM). The results showed that the composite films provide appropriate micro-bioenviroment for electrocatalysis of GOD. The modified electrode showed excellent electro-catalysis toward hydrogen peroxide(H2O2) and glucose(Glu). The experimental datas have showed fast responsive time(<5 s), high sensitivity(53 μA·mM-1), wide detection range(10-6～10-4 M), low detection limitvery(10-8 M). So PHEMA-b-PDMAEMA/GOD/rGOs composites have important pragmatic value in the filed of the enzyme biosensor.(2) Prepation of PHEMA-b-PDMAEMA/multi-walled carbon nanotubes (MWCNTs) modified electrode and its detection of bisphenol A in environmental pollutants. PHEMA-b-PDMAEMA/MWCNTs composites combining MWCNTs electric catalytic and proton PHEMA-b-PDMAEMA electrostatic adsorption ability, the electrode modified by them has the very high electrocatalysis performance for bisphenol A. Based on fast responsive time(<4 s), high sensitivity(55.9 μA·mM-1·cm-2), wide detection range(2×10-8～10-4 M), low detection limitvery(10-8 M), the high repeatability, the high stability and the strong anti-disturbance capability,the qualitative-quantitative analysis for the practical samples are showed by coating MWCNTs with diblock copolymer (PHEMA-b-PDMAEMA) film, So it fully embodies that the amino has potential value in food detection.(3) Prepation of PHEMA-b-PDMAEMA/Ag modified electrode and its electrocatalysis toward H2O2. The PHEMA-b-PDMAEMA/Ag composite film was synthesized by this method that Ag+ were loaded to surface of the porous diblock copolymer PHEMA-b-PDMAEMA by electrodeposition. The surface morphology and electrochemical behavior of the composite films are characterized by SEM, CV and i-T. Based on the photocatalysis of the transition metal Ag, the composite films realize the electro-catalysis to H2O2, and experimental datas show that the modified electrode have fast responsive time(<5 s), high sensitivity(107.1μA·mM-1), wide detection range(10-6～10-4 M) and low detection limitvery(10-8 M) toward H2O2. Therefore, the diblock copolymer has loaded Ag+ to simulate mechanism of enzyme, whice has important theoretical significance.(4) Based on PHEMA-b-PDMAEMA polymer of carbon/nitrogen composite coated nickel oxide microspheres non-enzyme sensor performance study:Nickel oxide microspheres(NiO-MS) were facilely synthesized through solvothermal method. Subsequently, carbon-nitrogen coated nickel oxide microspheres composite materials (NiO-MS@C/N) were prepared via pyrolysis of diblock copolymer PHEMA-b-PDMAEMA. The structure, elements, surface morphology and electrochemical behavior of the composite films were analyzed by EDS, XRD, SEM, CV and i-T. The result showed that the composites have perfect electrochemical properties and have fast responsive time(<3 s), high sensitivity(15 μA·mM-1·cm-2), wide detection range(10-6～10-3 M), low detection limitvery(10-8 M) and interference toward detection of H2O2.