Floris, Patrick

Gorey, Brian

Morrin, Aoife

Power, Aoife

White, Blánaid

DCU Online Research Access Service

Conducting Polymer Structures Housed in Thin-Layer Microfluidic Channels for ElectroanalysisAoife MorrinBlanaid White, Brian Gorey, Aoife Power, Patrick Floris64th Annual Meeting of the ISEQueretaro, Mexico, 8-13 September 20131Who we are?2Micro-fluidicsConducting Polymers3ElectrochemistryOutline Development of a microfluidic-based thin-layer electrochemical cell– Electropolymerisation of conducting polymer materials in microfluidic channels– Micro-structuring of materials on-chip Conducting polymers as coatings on capillary monoliths Towards stimuli-responsive chromatography4Integrating an electrochemical cell into microfluidicsA.C. Power, B. White, A .Morrin, Electrochimica Acta , 2013,  DOI:10.1016/j.electacta.2013.04.091Characterisation of thin layer microfluidic formatmlmDtlµµ 20035)2( 2/1<<<<A)0.20.4Increasing channel depth0.10.20.36Potential (V)-0.2 0.0 0.2 0.4 0.6Current (µA)-0.4-0.20.0WE length: 5 mmPotential (V)-0.2 0.0 0.2 0.4 0.6Current (µA)-0.3-0.2-0.10.0Conducting polymer films on-chipPotentialCurrent702040608010001234550100150200Polymer Height (µ m)Electrode length (mm)Cross section of Electrode (µm)Peak current - closed channel (µµ µµA)40Peak current - open channel (µµ µµA) 150020002500Self-limiting nature of thin-layer cell electropolymerisationThin layer flow cell polymerisationBatch cell polymerisationNo. of polymerisation cycles0 10 20 30 40 50Peak current - closed channel (020Peak current - open channel (050010008Self-limiting nature of thin layer cell electropolymerisation180 µm depthChannel depth (µm) Average PANI thickness (µm) after 50 polymerisation cycles 35 7.53 ± 0.2460 27.70 ± 6.58110 49.93 ± 1.53180 80.53 ± 6.8440935 µm depth60 µm depth110 µm depthNo. of polymerisation cycles0 10 20 30 40 50Peak current (µA)020 By creating inverse opal conducting polymer monolithic materials through sacrificial CC templates within channel (open channel format) Interesting structure for electrochemically responsive chromatography, drug delivery, flow through sensors on chip In terms of chromatography, it could enable high Can we create order in these materials on chip? internal surface areas of electroactive materials with periodic flow-through pores – Allow for precise electrochemical tuning of stationary phase before & during a separation to influence retention factors without need for gradient elution of mobile phase– Gain electrochemical control over hydrophobicity, pore size, ionic capacity10Colloidal crystal formation in the microchannel1) Capillary flow of PS suspension into channel2) Pinning of PS suspension to walls of the channel - evaporation flux, je3) Receding of meniscus line with continuous colloidal crystal growth – particle flux, jp and water flux, jw13LS2 LS6LS2 LS6Optimised CC structures in microchannelsUnimodalGorey et al. (2013) Fabrication of a 3-dimensionally ordered binarycolloidal crystal within a confined channel. Submitted to Chem.Mater.Conducting polymer monolithic structures+ EappTolueneYX13B. Gorey,  J. Galineau, B. White, M.R. Smyth,  A. Morrin, Electroanalysis 2012, 24,  1318 - 1323Dry & wetted states of CP monoliths - AFMDry State Wetted State*Electrochemically grown Ppy doped with DBS15Decreasing current density as it grows away from electrode surfaceOvercoming current density gradient using chemical polymerisationAPS + H2SO4PSPANIPS16Closed channel – flow through polymerisationOpen channel – batch polymerisationCore-shell flow-through bed comprised electroactive PANI In-situ polymerisation of styrene in the presence of a thermal initiator, a cross-linker, DVB and porogen, dodecanol Flush capillary with aniline, acid and oxidantFused silica capillary microfluidic channel171 coating PANI 2 coatings PANI 3 coatings PANICharacterisation of PANI-coated polymer monoliths18Switchable PANI-coated PS-co-DVB monolithDecrease pH515520525Detector response (mV)(i)13501450Detector response (mV)(ii)(b)Dedoped PANI CoatingDoped PANI Coating4854904955005055100 10 20 30 40 50 60 70Distance along capillary (mm)Detector response (mV)(b)(a)7508509501050115012500 10 20 30 40 50 60 70Distance along capillary (mm)Detector response (mV)(a)(c)Blank MonolithBlank MonolithCurrent challenge is to integrate an electrochemical cell into this capillary format – control conducting polymer oxidation state by application of a potentialCPs as separation phases in particulate-based packingsReduced OxidisedCaffeine TheophyllineChriswanto & Wallace, J. Liq. Chrom. & Rel Technol., 19:2457 (1996) 19CaffeineTheophilineTo Conclude…. What do we have?– Microfluidic thin layer electrochemical cell for conducting polymer bulk films and inverse opal structures Suitable format for exploiting EOF-driven flow?– Coatings of PANI on polymer monoliths in capillary format V. high surface areas, structurally supported films  Where to next?– Applications in LoC sensors, drug delivery, electrochemically-responsive chromatography20Thanks! Dr. Blánaid White  Dr. Damian Connolly Prof. Gordon Wallace Dr. Michael Higgins Brian Gorey Dr. Aoife Power Dr. Patrick Floris21aoife.morrin@dcu.ieCharacterisation of PANI-coated polymer monolithsScanning capacitivelycoupled contactless conductivity detection (sC4D)800100012001400160018000 10 20 30 40 50 60Distance along capillary (mm)Detector response (mV)Bare monolithPANI-coated monoliths

Conducting polymer structures housed in thin-layer microfluidic channels for electroanalysis

Name not available

http://doras.dcu.ie/19843/1/Oral_Presentation_13__Aoife_Morrin_ISE_2013_Mexico.pdf

Conducting polymer structures housed in thin-layer microfluidic channels for electroanalysis

Abstract

Similar works

Full text

Available Versions

DCU Online Research Access Service

Name not available