# US 9,518,950 B2 · Chemical sensor based on highly organized single walled carbon nanotube networks

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- Number: US 9,518,950 B2
- Document ID: US9518950B2
- Status: Granted
- Kind: B2
- Application number: 14/239,664
- Filed: 2012-08-20
- Published: 2014-07-17
- Granted: 2016-12-13
- Earliest claimed: 2011-08-19
- Assignees: Northeastern University
- Applicants: Ahmed Busnaina; Yung Joon Jung; Sivasubramanian Somu; Aniket Datar; Young Lae Kim
- Inventors: Ahmed Busnaina; Yung Joon Jung; Sivasubramanian Somu; Aniket Datar; Young Lae Kim
- Web page: https://patentgrep.com/patent/US9518950B2

## CPC

- G01N 27/26: by investigating electrochemical variables; by using electrolysis or electrophoresis
- B82Y 15/00: Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- G01N 27/127: {comprising nanoparticles}
- G01N 27/414: Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS
- G01N 27/4146: {involving nanosized elements, e.g. nanotubes, nanowires}
- G01N 33/0044: {Sulphides, e.g. H2S}
- H10K 10/20: Organic diodes
- H10K 85/221: {Carbon nanotubes}
- H10K 85/225: {comprising substituents}
- G01N 21/75: Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated (systems in which material is burnt in a flame or plasma G01N21/72, G01N21/73)
- G01N 21/77: by observing the effect on a chemical indicator
- 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)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

A carbon nanotube-based micron scale chemical sensor or sensor array is provided that enables the remote detection of hydrogen sulfide and other chemicals in a gas stream. The sensor is suitable for use in harsh environments of high temperature and pressure such as those encountered during petrochemical exploration and recovery. Multiplex sensor devices detect two or more chemical agents simultaneously, or they can detect conditions such as pressure, salinity, humidity, pH, or scale-forming ions. Incorporation of read out electronics and an RF signal generator into the sensor device enables it to communicate to a relay station or receiver for 3D mapping or other analysis. Methods are also provided for fabricating the chemical sensor device and using the device for detection.

## Claims

### Claim 1

A microscale sensor for detecting a chemical agent, the sensor comprising:
a substrate;
a conductive layer attached to a surface of the substrate, the conductive layer forming at least one pair of electrodes with an insulating gap between the electrodes; and
a conductive bridge consisting essentially of one or more functionalized single-walled carbon nanotubes bridging the gap between the electrodes;
wherein the one or more nanotubes are functionalized with a functional group that reacts with said chemical agent, whereby the conductivity of the conductive bridge is modified; and
wherein the functional group is TEMPO (2,2,6,6-tetramethylpiperidin-1-yl)oxy) or a TEMPO derivative and the chemical agent is hydrogen sulfide, or wherein the functional group is phenyl cyanide and the chemical agent is a mercaptan.

### Claim 2 (depends on 1)

The sensor of claim 1, wherein the single-walled carbon nanotubes are semiconducting.

### Claim 3 (depends on 1)

The sensor of claim 1, further comprising a microelectronic circuit for receiving and/or processing of an electrical signal from said electrodes.

### Claim 4 (depends on 1)

The sensor of claim 1, further comprising a transmitter for sending data obtained by the sensor to a remote receiver.

### Claim 5 (depends on 1)

The sensor of claim 1, comprising a plurality of conductive bridges of one or more functionalized single-walled carbon nanotubes, each bridging a gap between said electrodes.

### Claim 6 (depends on 5)

The sensor of claim 5, wherein the plurality of bridges forms a two-dimensional array of single-walled carbon nanotubes.

### Claim 7 (depends on 1)

The sensor of claim 1 which is a multiplex sensor capable of detecting two or more different chemical agents.

### Claim 8 (depends on 1)

The sensor of claim 1 which specifically detects hydrogen sulfide and wherein the functional group is TEMPO (2,2,6,6-tetramethylpiperidin-1-yl)oxyl) or a TEMPO derivative.

### Claim 9 (depends on 8)

The sensor of claim 8, wherein the wherein the functional group is TEMPO derivative, and the TEMPO derivative is 4-amino TEMPO or 4-hydroxy TEMPO.

### Claim 10 (depends on 1)

The sensor of claim 1 which detects said chemical agent at temperatures up to 180° C.

### Claim 11 (depends on 1)

The sensor of claim 1 which detects said chemical agent at pressures up to 20 kpsi.

### Claim 12 (depends on 1)

A method of detecting a chemical agent in a sample, the method comprising the steps of:
(a) providing the microscale sensor of claim 1;
(b) measuring a baseline conductance value of the conductive bridge of the sensor in the absence of the sample;
(c) exposing the conductive bridge to the sample; and
(d) measuring a change in the conductance of the bridge in the presence of the sample compared to the absence of the sample, wherein the change in conductance indicates the presence or absence of the chemical agent in the sample;
wherein the chemical agent is hydrogen sulfide or a mercaptan.

### Claim 13 (depends on 12)

The method of claim 12, wherein the amount or concentration of the chemical agent in the sample is determined by comparing the change in conductance value to a calibration for said chemical agent.

### Claim 14 (depends on 12)

The method of claim 12, wherein the sample is a gas.

### Claim 15 (depends on 14)

The method of claim 14, wherein the relative humidity of the gas is controlled by adding water vapor to the gas or removing water vapor from the gas prior to exposing the conductive bridge to the gas.

### Claim 16 (depends on 12)

The method of claim 12, wherein two or more chemical agents are detected simultaneously.

### Claim 17 (depends on 12)

The method of claim 12, wherein conductance data from the sensor are processed in a data processor integrated into the sensor device.

### Claim 18 (depends on 12)

The method of claim 12 wherein conductance data from the sensor are transmitted to a remote receiver.

### Claim 19 (depends on 17)

The method of claim 17, wherein processed data from the data processor are transmitted to a remote receiver.

### Claim 20 (depends on 18)

The method of claim 18, wherein data are transmitted from a plurality of sensors and a map of the presence or concentration of the chemical agent is produced.

### Claim 21 (depends on 19)

The method of claim 19, wherein data are transmitted from a plurality of sensors and a map of the presence or concentration of the chemical agent is produced.