Preparation Of Polypyrrole Microcapsules And Their Application To All Solid Zinc Ion Selective Electrodes

Hollow polymeric microcapsules or nanocapsules have the optical,electrical and catalytic performance,able to encapsulate a variety of guest molecules such as drugs,enzymes,dyes,genes and nanoparticles.These molecules can released by controlling reaction condition with a certain speed to achieve the purpose of treatment and dying,which render them to have potential application value in biomedical,chemical analysis and industrial production.Thus for wall materials of hollow structure have also become research hotspot.Polypyrrole is a kind of conductive polymers,which is hardness,higher density with five membered heterocyclic rings structure,and its excellent electrical conductivity,environmental stability,non-toxicity and biocompatibility attract much attention to the preparation of superconducting materials,biological sensors and electrode materials.This paper using in situ polymerization method to deposite polypyrrole on the surface of water-in-oil emulsion droplet.Oxidize monomer from pyrrole to produce polypyrrole chains by benzoyl peroxide(BPO),sodium dodecylbenzenesulfonate(DBSNa)and p-toluene sulphonic acid(TsOH)as dopants to enhance the conductivity of polypyrrole which encapsuled core material is zinc chloride aqueous solution.The resulting morphology and structures of the prepared polypyrrole microcapsules were characterized by optical microscope,environmental scanning electron microscope(ESEM),scanning electron microscope(SEM),optical fourier transform infrared spectrometer(FTIR),X-ray photoelectron spectroscopy(XPS)and Raman spectroscopy.Then using the better performance of the polypyrrole microcapsules prepared as conductive layer of all-solid-state ion selective electrode to improve the conversion efficiency of ion and electron,increasing the conductivity of zinc ion selective electrode.Using Electrochemical Workstation and Acidity Meter to analyze cyclic voltammetry,ac impedance spectra and nernst selective response of the solid-state zinc ion selective electrode.The experimental research show that the size of microcapsules improved with the increase of zinc ion concentration(When it's up to 20%,the size is 45,m).BPO as oxidant and TsOH as dopant were increased to 123.71%and 4.12%,respectively,the thickness of microcapsules' wall increase gradually,and have certain supporting function.Forming uniform particle size,smooth surface and local denting.With these kind of polypyrrole microcapsules build solid-state ion selective electrodes in pH range from 3 to 7 has the stable selective.The linear range from 10-5 to 10-1 M,the detection limit is 2.45×10-6 M,the slope is 19.5 mV/dec,and has good electric double layer capacitors.The impedance of internal charge transfer is smaller infer that the ISE has the perfect electrical conductivity.