# US 11,442,013 B2 · Sensor membrane, sensor cap and/or optical sensor and method for manufacturing a sensor membrane > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,442,013 B2 - Document ID: US11442013B2 - Status: Granted - Kind: B2 - Application number: 16/527,521 - Filed: 2019-07-31 - Published: 2020-02-06 - Granted: 2022-09-13 - Earliest claimed: 2018-08-01 - Assignees: Endress+Hauser Conducta GmbH+Co. KG - Applicants: Endress+Hauser Conducta GmbH+Co. KG - Inventors: Andreas Löbbert - Web page: https://patentgrep.com/patent/US11442013B2 ## CPC - G01N 21/643: {non-biological material} - G01N 21/645: {Specially adapted constructive features of fluorimeters} - G01N 21/77: by observing the effect on a chemical indicator - G01N 21/7703: {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)} - G01N 2021/6432: {Quenching} - G01N 2021/6434: {Optrodes} - G01N 2021/772: {Tip coated light guide} - G01N 2021/7786: {Fluorescence} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) The sensor membrane according to claim 1, wherein the microstructure-forming particles are spherical or capsule-shaped components of the outer layer. ### Claim 3 (depends on 1) The sensor membrane according to claim 1, wherein the omniphobic surface has a pin cushion structure or a honeycomb structure. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 4) 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. ### Claim 6 (depends on 4) 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. ### Claim 7 (depends on 1) 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. ### Claim 8 (depends on 7) 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. ### Claim 9 (depends on 7) 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. ### Claim 10 (depends on 1) 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. ### Claim 11 (depends on 1) 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. ### Claim 12 (depends on 1) 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. ### Claim 13 (depends on 1) 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. ### Claim 14 (depends on 13) The sensor membrane according to claim 13, wherein the grafted side chains have an average length between 10 A and 70 A. ### Claim 15 (depends on 1) 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. ### Claim 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. ### Claim 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. ### Claim 18 (depends on 17) 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. ### Claim 19 (depends on 17) 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. ### Claim 20 (depends on 17) 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. ### Claim 21 (depends on 20) The method according to claim 20, further comprising: modifying photochemically a surface structure of the sensor membrane after grafting by applying a mask at a wavelength between 200 and 1000 nm. ### Claim 22 (depends on 21) The method according to claim 21, wherein the step of modifying photochemically the surface structure of the sensor membrane includes applying a reactive liquid to the surface structure.