ELECTROCONDUCTIVE POLYMER MICROSENSOR ELECTRODES (EPMEs)

(Conductive Polymer Sensors)

Introduction and Background Ø EPMEs comprise fully contiguous and specifically adhered (via covalent bond formation) thin films of electroconductive polymers fabricated on inert interdigitated microsensor electrode array devices (IMEs). These EPME devices serve as chemically sensitive solid-state transducers in various chemical and biological sensors and as gas/vapor sensors. Ø EPMEs are your direct means for the simultaneous measurement of the electrical conductivity (conductimetric sensor), electrode potential (potentiometric sensor), and current (amperometric sensor) of thin, electroconductive polymer films on IME devices. With the associated Electroconductive Polymer Sensor Interrogation System (EPSIS 240II CS), you are provided with the computerized sensor interrogation and data acquisition hardware for the simultaneous study of the electrochemical and electrical characteristics of the electroactive polymer films - electroconductive polymer sensor technology. Ø Microfabricated from magnetron sputter-deposited gold or e-gun vapor-deposited platinum, these devices are supplied with three possible proprietary formulations of electroconductive polymers - polyaniline, polypyrole and poly(3-hexylthiophene). Only 10 mincron line and space dimensions are available for the EPME devices. However, our three device configurations are available; Monolith (M), Combined Differential (CD), and Full Differential (FD). The EPME is supplied in the form of a fully packaged (P) electrode with leadwires attached and the device encapsulated using a chemically resistant epoxy resin to seal the bonding pads into a delrin electrode body. Ø EPME transducers possessing surface-available carboxylic acid (-COOH), primary amine (-NH2), primary alcohol (-OH), or free sulfhydryl (thiol) (-SH) groups for the specific attachment and immobilization of biologically active polypeptides, enzymes, antibodies, enzyme-linked antibodies, DNA fragments, as well as inorganic and other indicator molecules may also be obtained under our Bioanalytical Biosensors product line or under joint product development contract. Back to Top Applications of EPMEs Applications of EPMEs in research and product development include: Ø In chemical and biosensor research and development: The high sensitivity of these organic, polymeric, semiconducting films to changes in redox state, along with the solid state construction and small device size, make these devices ideally suited for research and development of chemical and biosensor applications. Ø In volatile organic compound (VOC) sensor research and development: The ability of these polymer films to reversibly absorb and desorp organic vapors from within their microstructure with simultaneous change in electrical conductivity makes these sensors well suited for the development of VOC probes. Ø As chemoresistive sensor elements in multi-element arays: Several differently responding, but singularly non-specific, sensor elements may be assembled into multi-element arrays for the recognition and monitoring of analytes of interest. Back to Top Technical Specifications Ø Chip Substrate: Schott D263 Borosilicate Glass Dielectric Constant, Epsilon(r) at 1 MHz = 6.7 Dielectric Loss Angle, tan delta, at 1 MHz = 61 x 10-4 Electrical Resistivity (50 Hz) (250 C) = 1.6 x 108 ohm cm Coefficient of Linear Thermal Expansion, * 20-300 = 7.2 x 10-6 K-1 Refractive Index at 20 C, ne ( Lambda = 546.1 nm) = 1.5249 Ø Metallization: 100 Å Ti / 1000 Å Au or Pt Digit length, d, (microns) = 4,985 No. of digit pairs per sensor, N = 50 Digit Width, a, (microns) = 10 Interdigit Space, a, (microns) = 10 Spatial Periodicity, lambda, (microns) = 40 Zaretsky Meander Length, M, (cm) = 24.93 cm Center Line or Serpentine Length (cm) = 49.55 cm Cell Constant (cm-1) = 0.040 cm-1 Ø IME Chip Dimensions (l x w x t) for the Un-packaged Die (EPME devices are available in FD design only) Full Differential, FD = 1.75 x 1.00 x 0.05 cm Ø Packaging (all EPME devices are fully packaged) Electrode Body: Delrin Encapsulant: Epoxy header. Leadwires: 28 AWG stranded copper, shielded, and PVC jacketed. Back to Top Methods Chemoresistance responses of EPME devices may be obtained form a wide assortment of interogation hardware. These fall into three categories. Ø Dedicated Electroconductive Polymer Sensor Interrogation System (EPSIS). Ø DC Resistance Measurements performed with: Simple multimeters set to resistance mode with operator recording of displayed data. Sophisticated multimeters with data logging capability or computer interfaced (commonly RS232, IEEE488, or USB). Electrometers with a computer interface (commonly RS232, IEEE488, or USB). Ø Complex Impedance response performed with: Combined Function Generator and Lock-in Amplifier. Transfer Function Analyzers. AC-Impedance Analyzers. Back to Top Application Notes For further information, request Application Notes: Ø IME1 - Interdigitated Microsensor Electrodes: Applications and References. Ø IME2 - Conductimetric Urea Biosensor Formed From Interdigitated Microsensor Electrodes Ø IME3 - Cleaning Procedures Electroconductive Polymer Microsensor Electrode (EPMETM) is the trade name for a family of non-specific sensor devices developed by ABTECH. Back to Top Contact: Ann M. Wilson, Manager, Applications Development ABTECH Scientific, Inc. 800 East Leigh Street, Suite G24, Richmond, Virginia 23219 Telephone Number: +1-804-783-7829 Fax Number: +1-804-783-7830 e-mail: sales@abtechsci.com