Metal oxide pH sensor

Patent metadata

Field	Value
Publication number	US-10139365-B2
Application number	US-201515507850-A
Country	US
Kind code	B2
Filing date	Aug 28, 2015
Priority date	Sep 1, 2014
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

A pH sensor comprising a metal oxide-polymer composite, comprising: a continuous polymer resin matrix; and a solid particulate, component dispersed in the polymer resin matrix comprising (i) metal oxides and (ii) a particulate carbon-based conductor wherein the metal oxides comprise Ta2O5 and RuO2 in a weight ratio of Ta2O5:RuO2 (on the basis of weight of metal component) in the range of from 90:10 to 10:90.

First claim

The invention claimed is:

1. A pH sensor comprising a metal oxide-polymer composite, comprising:
a continuous polymer resin matrix; and
a solid particulate component dispersed in the polymer resin matrix comprising (i) particulate metal oxides and (ii) a particulate carbon-based conductor,
wherein the particulate metal oxides comprise Ta 2 O 5 and RuO 2 in a weight ratio based on Ta:Ru in the range of from 90:10 to 10:90.

2. A pH sensor according to claim 1 wherein the composite comprises a weight ratio Ta 2 O 5 :RuO 2 in a weight ratio based on Ta:Ru in the range of from 70:30 to 30:70.

3. A pH sensor according to claim 1 , wherein the solid particulate component comprising the particulate metal oxides and the particulate carbon-based conductor constitutes at least 40% by weight of the composite composition.

4. A pH sensor according to claim 1 , wherein the solid particulate component comprises in the range of from 60% to 80% by weight of the composite.

5. A pH sensor according to claim 1 , wherein the particulate carbon-based conductor comprises a material selected from the group consisting of particulate carbon, graphite, fullerenes and carbon fibre.

6. A pH sensor according to claim 1 , wherein Ta 2 O 5 and RuO 2 constitute at least 80% by weight of a total metal oxide content of the composite.

7. A pH sensor according to claim 1 , wherein the particulate metal oxides comprise, in addition to Ta 2 O 5 and RuO 2 , further metal oxides, the further metal oxides comprising up to 20% by weight of a total metal oxide component of the metal oxide-polymer composite.

8. A pH sensor according to claim 7 , wherein the further metal oxides comprise one or more metal compounds selected from the group consisting of PtO 2 , IrO 2 , TiO 2 , Er 2 O 3 , ZrO 2 , Al 2 O 3 , RhO 2 , SnO 2 , La 2 O 3 and Li 2 O.

9. A pH sensor according to claim 1 , wherein the particulate carbon-based conductor is selected from the group consisting of particulate carbon and particulate graphite.

10. A pH sensor according to claim 1 , wherein the particulate metal oxides are of particle size less than 100 microns.

11. A pH sensor according to claim 1 , wherein the polymer matrix comprises a resin selected from the group consisting of; polystyrene, polyurethane, polyethylene, acrylates, methacrylates, vinyl resins, vinyl ester resin, phenol resin, epoxy resin and mixtures thereof.

12. A pH sensor according to claim 1 , wherein the metal oxide-polymer composite comprises:
the resin polymer matrix in an amount of at least 15% by weight of the composite, wherein the solid particulate component dispersed in the matrix comprises:
(i) particulate Ta 2 O 5 in an amount of at least 5% by weight, determined as Ta, of the composite;
(ii) particulate RuO 2 in an amount of at least 5% by weight, determined as Ru, of the composite; and
(iii) particulate graphite in an amount of at least 5% by weight of the composite; and optionally
(iv) up to 5% by weight of the composite of other metal oxides selected from the group consisting of PtO 2 , IrO 2 , TiO 2 , Er 2 O 3 , ZrO 2 , Si 3 N 4 , Al 2 O 3 and mixtures thereof.

13. A method of preparing the pH sensor according to claim 1 , the method comprising dispersing the solid particulate component comprising the metal oxides and the carbon-based conductor in a hardenable liquid resin and hardening the liquid resin to form the polymer resin matrix with the dispersed solid particulate component dispersed therein, wherein the metal oxides comprise Ta 2 O 5 and RuO 2 in a weight ratio based on Ta:Ru in the range of from 90:10 to 10:90.

14. A method of preparing a pH sensor according to claim 13 , wherein the polymer resin matrix comprises an epoxy resin.

15. A pH sensor according to claim 1 , further comprising a substrate to which the metal oxide-polymer composite has been applied.

16. A method of preparing a pH sensor according to claim 13 , wherein the hardenable liquid resin comprising the dispersed solid particulate component is applied to a substrate by printing and is hardened on the substrate.

17. A pH sensor according to claim 1 , wherein the composite has a particulate Ta 2 O 5 content, determined as Ta metal component, of 5% to 25% by weight of the composite.

18. A pH sensor according to claim 1 , wherein the composite has a particulate RuO 2 content, determined as Ru metal component, of 5% to 25% by weight of the composite.

Assignees

• Commw Scient Ind Res Org

Inventors

• Chen Miao
• Vepsalainen Mikko

Classifications

• G01N27/302

  pH sensitive, e.g. quinhydron, antimony or hydrogen electrodes (ion selective electrodes G01N27/333, glass electrodes G01N27/36) · CPC title

• G01N27/4167 Primary

  pH (electrodes therefor G01N27/302, G01N27/36) · CPC title