# US 2012/0073388 A1 · Force sensing compositions, devices and methods

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- Number: US 2012/0073388 A1
- Document ID: US20120073388A1
- Status: Published application
- Kind: A1
- Application number: 13/322,069
- Filed: 2010-05-21
- Published: 2012-03-29
- Earliest claimed: 2009-05-22
- Assignees: University of New Brunswick
- Inventors: Luis Paulo Felipe Chibante
- Web page: https://patentgrep.com/patent/US20120073388A1

## CPC

- G01L 1/20: by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids (of piezo-resistive materials G01L1/18); by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## Abstract

A composite comprising a pliable base material and nanoscale anisotropic conductive particles; whereby deformation of the composite causes a change in the electrical conductivity of the composite.

## Claims

### Claim 1

A composite comprising:
a pliable base material and nanoscale conductive particles; whereby deformation of the composite causes a change in the electrical conductivity of the composite.

### Claim 2 (depends on 1)

The composite of claim 1 wherein the pliable material is an elastomer.

### Claim 3 (depends on 2)

The composite of claim 2 wherein the conductive particles are anisotropic.

### Claim 4 (depends on 3)

The composite of claim 3 wherein the conductive particles are tubular.

### Claim 5 (depends on 2)

The composite of claim 2 wherein the conductive particles are selected from the group consisting of nanotubes, nanorods, nanowhiskers and nanowires.

### Claim 6 (depends on 2)

The composite of claim 2 wherein the conductive particles are carbon nanotubes.

### Claim 7 (depends on 2)

The composite of claim 2 wherein the conductive particles have diameters less than about 500 nm.

### Claim 8 (depends on 2)

The composite of claim 2 wherein the conductive particles have a length-to-diameter ratio of greater than about 2.

### Claim 9 (depends on 2)

The composite of claim 2 wherein the conductive particles are platelets.

### Claim 10 (depends on 2)

The composite of claim 2 wherein the conductive particles are selected from the group consisting of carbon and conductive metals.

### Claim 11 (depends on 2)

The composite of claim 2 wherein the elastomer is polydimethyl-siloxane.

### Claim 12 (depends on 2)

The composite of claim 2 further comprising a substrate and wherein the composite forms a piezoresistive layer on the surface of the substrate.

### Claim 13 (depends on 3)

A force sensing device comprising the composite of claim 3 further comprising at least two electrodes in electrical contact with the substrate and wherein the electrodes are connectable to a power supply.

### Claim 14 (depends on 13)

The device of claim 13 wherein the electrodes are on opposing surfaces of the composite.

### Claim 15 (depends on 13)

The device of claim 13 wherein the electrodes are on the same surface of the composite.

### Claim 16 (depends on 13)

The device of claim 13 wherein the composite is a thin film.

### Claim 17 (depends on 16)

The device of claim 16 wherein the thin film is printed on the substrate.

### Claim 18 (depends on 1)

A method for detecting applied force comprising:
providing the composite of claim 1;
applying a voltage and/or current to the composite;
taking a first measurement of resistivity and/or conductivity of the composite;
deforming the substrate;
taking a second measurement of resistivity and/or conductivity of the composite;
determining the difference between the first and second measurements; and
correlating the difference to the degree of deformation

### Claim 19 (depends on 18)

The method of claim 18 further comprising correlating the difference to the magnitude of a force applied to the composite.