Sensor membrane, sensor cap and/or optical sensor and method for manufacturing a sensor membrane

Patent metadata

Field	Value
Publication number	US-11442013-B2
Application number	US-201916527521-A
Country	US
Kind code	B2
Filing date	Jul 31, 2019
Priority date	Aug 1, 2018
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

A sensor membrane for an optical sensor, wherein the outer layer in contact with the medium and/or a layer adjacent thereto has a graft copolymer to form an omniphobic surface in contact with the medium, as well as a sensor cap and/or an optical sensor and a method for manufacturing the sensor membrane.

First claim

The invention claimed is:

1. A sensor membrane for an optical sensor, comprising:
an outer layer embodied to contact a liquid medium,
wherein the outer layer includes a graft polymer or a graft copolymer forming an omniphobic surface in contact with the liquid medium, and
wherein the outer layer further includes microstructure-forming particles and a nanostructure grafted onto the microstructure-forming particles.

2. The sensor membrane according to claim 1 , wherein the microstructure-forming particles are spherical or capsule-shaped components of the outer layer.

3. The sensor membrane according to claim 1 , wherein the omniphobic surface has a pin cushion structure or a honeycomb structure.

4. The sensor membrane according to claim 1 ,
wherein the outer layer includes a reactive matrix material,
wherein the microstructure-forming particles are immobilized in the outer layer and form a microstructure,
wherein the nanostructure is formed as grafted side chains covalently bound to the reactive matrix material located on the microstructure or covalently bound directly on the microstructure, and
wherein the microstructure is selected from a group consisting of silicon oxide particles, titanium oxide particles, polystyrenes, styrene polymers, polybutadiene, natural substance capsules, and hybrids of the aforementioned compounds.

5. The sensor membrane according to claim 4 ,
wherein the microstructure-forming particles are scaffold structures of diatoms or exines of spores or exines of pollen.

6. The sensor membrane according to claim 4 , wherein the microstructure is formed by:
grafting microstructure-forming particles comprising polybutadiene or polybutadiene-coated microstructure-forming particles with ethoxysilane side chains;
grafting microstructure-forming particles comprising polybutadiene or polybutadiene-coated microstructure-forming particles with methoxysilane side chains; or
modifying an exine with hydroxyl groups and double bonds.

7. The sensor membrane according to claim 1 , wherein the graft polymer comprises grafted side chains received by grafting one or several of the following components to a matrix material comprising a polymer:
at least one hydrolytically cross-linkable group as a chain extender or as a chain end group and/or as a chain end group, and at least one radical cross-linkable group as a chain extender and/or as a chain end group.

8. The sensor membrane according to claim 7 , wherein the at least one hydrolytically cross-linkable group, when it is used as a chain extender, is a mono- or bifunctional silane chosen from the group consisting of: dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hexamethyldisoxane, octamethylcyclotetrasiloxane, polydimethylsiloxane, polydimethylsiloxane, polydimethylsiloxane T22, polydimethylsiloxane T35 and polydimethylsiloxane T46; and when it is used as a chain end group, it is chosen from the group consisting of: trimethyoxysiloxane and triethylethoxysiloxane.

9. The sensor membrane according to claim 7 , wherein the at least one radical cross-linkable group, when it is used as a chain extender, is a monofunctional monomer chosen from the group consisting of: perfluorinated groups, perfluoroalkyl groups, alkyl with alkynyl or vinyl groups, styrene, acrylate, acrylamide, methacrylate, methacrylamide, vinyl ester and vinyl amide groups; and when it is used as a chain end group, it is chosen from the group consisting of: 2,2,6,6-tetramethyl-piperidinyl-1-oxy (TEMPO), 2,2,5-trimethyl-4-phenyl-3-azahexane-3-oxyl (TIPNO), N-tert-butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)] nitroxide (SG1), HALS compounds, thiols, hydrocarbon radicals, and amines.

10. The sensor membrane according claim 1 , wherein the microstructure-forming particles are selected from the following group: silicon oxide particles, titanium oxide particles, modified and/or unmodified natural substance capsules, scaffold structures of diatoms, exines of spores and/or exines of pollen, in particular of Lycopodium clavatum.

11. The sensor membrane according to claim 1 , further comprising:
a further layer including a further matrix material, said further layer being positioned underneath the outer layer,
wherein the sensor membrane has a topographically structured, nubby surface formed by the microstructure-forming particles, a number of which are partly embedded in the further matrix material and protrude from the further matrix material in the form of nubs.

12. The sensor membrane according to claim 1 , further comprising:
an adhesion-promoting layer for bonding to a substrate;
a layer sensitive to an analyte, wherein the layer sensitive to an analyte includes luminophore;
at least one of: a reflective layer, a diffusion layer, and an optically insulating layer; and
a top layer including a surface polymer, wherein the top layer has grafted side chains on the surface.

13. The sensor membrane according to claim 1 , further comprising:
a plurality of nanostructures grafted onto the microstructure-forming particles,
wherein each nanostructure is formed as a grafted side chain, and
wherein an average distance of a side chain from a directly adjacent side chain is between 2 A (angstroms) and 200 A.

14. The sensor membrane according to claim 13 , wherein the grafted side chains have an average length between 10 A and 70 A.

15. The sensor membrane according to claim 1 , further comprising:
a hydrolyzable protective layer arranged on the outer layer, where in the protective layer is embodied to dissolve at least partially when exposed to the liquid medium.

16. A sensor cap of an optical sensor, comprising:
a sensor membrane, including
an outer layer embodied to contact a liquid medium, wherein the outer layer includes a graft polymer or a graft copolymer forming an omniphobic surface in contact with the liquid medium and wherein the outer layer further includes microstructure-forming particles and a nanostructure grafted onto the microstructure-forming particles; and
a layer with a graft copolymer beyond the sensor membrane.

17. A method for manufacturing a sensor membrane, comprising:
providing an arrangement of a plurality of functional layers of a sensor membrane, wherein an outer layer in contact with the medium and/or a layer of the sensor membrane adjacent thereto has a surface with microstructure-forming particles embedded in a matrix material of the respective layer; and
grafting a compound onto the microstructure-forming particles and/or onto a reactive matrix material covering the microstructure-forming particles by graft polymerization or graft copolymerization, thus forming a nanostructure by forming side chains.

18. The method according to claim 17 , wherein parts of the microstructure-forming particles are protruding from the matrix material of the respective layer in the form of nubs.

19. The method of claim 17 , wherein the microstructure-forming particles are chosen from a group consisting of: natural substance capsules, inorganic microparticles, and polystyrene particles.

20. The method according to claim 17 , further comprising:
grafting side chains onto the reactive matrix material and/or onto the microstructure-forming particles, using temperature-activatable, radicals and/or ions and/or thermal initiators and/or photoinitiators and/or radical-forming means and thereby form nanostructures.

21. The method according to claim 20 , further comprising:
modifying photochemically a surface structure of

Assignees

• Endress Hauser Conducta Gmbh Co Kg

Inventors

• Löbbert Andreas

Classifications

• G01N21/7703

  using reagent-clad optical fibres or optical waveguides (using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B) · CPC title

• G01N21/645

  Specially adapted constructive features of fluorimeters · CPC title

• G01N21/643 Primary

  non-biological material · CPC title

• G01N2021/6434

  Optrodes · CPC title

• G01N2021/6432

  Quenching · CPC title