Global Patent Index - EP 0931183 A4

EP 0931183 A4 2001-03-07 - DEPOSITION OF THIN ELECTROCONDUCTIVE POLYMER FILM OF DESIRED RESISTANCE FOR GAS SENSING APPLICATIONS

Title (en)

DEPOSITION OF THIN ELECTROCONDUCTIVE POLYMER FILM OF DESIRED RESISTANCE FOR GAS SENSING APPLICATIONS

Title (de)

ABSCHEIDUNG VON DÜNNEN, ELEKTRISCH LEITENDEN POLYMERFILMEN MIT GEWÜNSCHTEM WIDERSTAND, FÜR GASDEDTEKTIERANWENDUNGEN

Title (fr)

DEPOSITION D'UN FILM POLYMERE MINCE ELECTROCONDUCTEUR D'UNE RESISTANCE DESIREE, UTILISABLE DANS LE DOMAINE DE LA DETECTION DES GAZ

Publication

EP 0931183 A4 (EN)

Application

EP 97942321 A

Priority

  • NZ 9700123 W
  • NZ 29933396 A
  • NZ 29933296 A

Abstract (en)

[origin: WO9811279A1] Electrodeposition of thin sensing polymers on microelectrodes, grown apparently to the same parameters, show wide resistance variations. Thicker films of more consistent resistance are too slow to respond, because of the time taken for the target gas to diffuse through them. These drawbacks may be overcome by tailoring thin electroconductive polymer films to the resistance required, by measuring the resistance at intervals during deposition and continuing to deposit film, until a high or predetermined resistance is obtained. This may be effected in a time multiplexed fashion, in which an electrodeposition current pulse is applied to the electrodes, followed by a period in which the inter-electrode is measured using a voltage below the threshold, at which electrodeposition occurs. Alternatively, an AC method, capable of measuring high impedance at low voltages may be employed and the measurement of resistance may be carried out simultaneously with the deposition. A typical electroconductive polymer is polypyrrole, which may ber deposited at a potential of 750 - 900 mV. Pyrrole forms an oligomer from solution prior to deposition and polymerisation is completed in situ. The substrate is preferably a microelectrode array, with elements about 1000 mu long, several mu wide and spaced about 10 mu apart, (i.e., within the distance, wherein the concentration decreases by a factor of 3). A counter electrode to supply the required current, in either a potentio or galvano-static mode is also required. In operation as a gas sensor, the power should be as low as possible to ensure that resistance changes represent a gas response alone, unaffected by measurement factors.

IPC 1-7 (main, further and additional classification)

C25D 13/08; C25D 13/12; C25D 13/16; C25D 13/18; H01C 17/22

IPC 8 full level (invention and additional information)

C25D 13/12 (2006.01); C25D 13/18 (2006.01); H01C 17/22 (2006.01)

CPC (invention and additional information)

C25D 13/12 (2013.01); C25D 13/18 (2013.01); H01C 17/22 (2013.01)

Citation (search report)

  • No further relevant documents disclosed
  • See also references of WO 9811279A1

Designated contracting state (EPC)

DE ES FR GB GR IT PT

EPO simple patent family

WO 9811279 A1 19980319; AU 4404497 A 19980402; AU 733671 B2 20010524; EP 0931183 A1 19990728; EP 0931183 A4 20010307

INPADOC legal status


2003-10-08 [18D] DEEMED TO BE WITHDRAWN

- Effective date: 20030331

2001-03-07 [A4] SUPPLEMENTARY SEARCH REPORT

- Effective date: 20010123

2001-03-07 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A4

- Designated State(s): DE ES FR GB GR IT PT

2001-03-07 [RIC1] CLASSIFICATION (CORRECTION)

- Free text: 7C 25D 13/08 A, 7C 25D 13/12 B, 7C 25D 13/16 B, 7H 01C 17/22 B, 7C 25D 13/18 B, 7C 25D 13/10 -, 7H 01C 17/06 -, 7H 01C 17/16 -

1999-07-28 [17P] REQUEST FOR EXAMINATION FILED

- Effective date: 19990406

1999-07-28 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A1

- Designated State(s): DE ES FR GB GR IT PT