Functional surfaces for liquid crystal-based detection of chlorine gas
AssigneeWisconsin Alumni Research Foundation
InventorsEmmanouil Mavrikakis, Nicholas Abbott, Tibor Szilvasi, Nanqi Bao, Huaizhe Yu
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Abstract
Liquid crystal-based devices for detecting chlorine in a sample and methods of using such devices to detect chlorine are disclosed. Such devices have a substrate surface that includes either metal cations or a metal that is in contact with a composition that includes a liquid crystal. When the device is contacted with a sample that contains chlorine, an observed change in the orientational ordering of the liquid crystal signals the presence of the chlorine. In the absence of chlorine, no change in orientational ordering occurs.
Claims20
A device for detecting chlorine gas, the device comprising:
- (a) a substrate having a surface comprising either:
- (i) one or more metal cations capable of binding a liquid crystal strongly enough to cause homeotropic ordering of the liquid crystal in contact with the substrate surface and having an oxidized state that is not capable of binding the liquid crystal strongly enough to cause homeotropic ordering of a liquid crystal in contact with the substrate surface, wherein the one or more metal cations are capable of being oxidized to the oxidized state by chlorine gas, and wherein the one or more metal cations are not capable of being oxidized to the oxidized state by the oxygen in air;
- or
- (ii) a metal capable of binding a mixture comprising a liquid crystal and a sensitizer molecule strongly enough to cause homeotropic ordering of such a mixture in contact with the substrate surface in the absence of chlorine, but not when chlorine atoms are dissociatively bound to the substrate surface;
- and
- (b) a composition comprising a liquid crystal that is in contact with the substrate surface, wherein if the substrate surface comprises the metal, the composition further comprises the sensitizer molecule;
- wherein the liquid crystal is capable of changing its orientational ordering when Cl2 comes in contact with the substrate surface.
A method for detecting the presence of chlorine in a sample comprising:
- (a) contacting a substrate surface with the sample, wherein the substrate surface comprises either:
- one or more metal cations capable of binding a liquid crystal strongly enough to cause homeotropic ordering of the liquid crystal in contact with the substrate surface and having an oxidized state that is not capable of binding the liquid crystal strongly enough to cause homeotropic ordering of a liquid crystal in contact with the substrate surface, wherein the one or more metal cations are capable of being oxidized to the oxidized state by chlorine gas, and wherein the one or more metal cations are not capable of being oxidized to the oxidized state by the oxygen in air;
- or
- (ii) a metal capable of binding a mixture comprising a liquid crystal and a sensitizer molecule strongly enough to cause homeotropic ordering of such a mixture in contact with the substrate surface in the absence of chlorine, but not when chlorine atoms are dissociatively bound to the substrate surface;
- (b) contacting the substrate surface with a composition comprising a liquid crystal, wherein if the substrate surface comprises the metal, the composition further comprises a sensitizing agent;
- and
- (c) observing the orientational ordering of the liquid crystal in the device;
- wherein an observed change in the orientational ordering of the liquid crystal from the expected orientational ordering of the liquid crystal in the absence of chlorine indicates that chlorine is present in the sample.
Dependencies are inferred from the claim text.