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Conductivity hydrogels composite material sensitized to humidity variation

A conductive hydrogel and composite material technology, applied in the analysis of materials, the use of electrical devices, the use of electromagnetic means, etc., can solve the problems of sudden changes in electrical properties, poor dimensional stability, and small resistance changes, and achieve a large degree of design freedom. Effect

Inactive Publication Date: 2009-03-11
SHENYANG JIANZHU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Moreover, the change range of its conductivity is only 0.85-1.4mS / cm (conductive gel with Cu addition), and 4.5-2.0mS / cm (carbon fiber / graphite / conductive gel), which generally has the disadvantage of small resistance change; Moreover, they are all made into powder samples, and the dimensional stability after water absorption / dehydration is poor, so they cannot be practically used as humidity sensors.
None of the prior art involves the change of gel network expansion and contraction caused by different water content in the process of responding to environmental changes, resulting in a sudden change in electrical properties to water content changes

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] For the preparation of carbon nanotube / polyacrylamide composite materials and devices, add 100 mL of deionized In the water, nitrogen gas was introduced to remove the oxygen in the water, and the carbon nanotubes were uniformly dispersed in the water to form a stable suspension after ultrasonic oscillation for 4 hours; 0.133g of N, N methylenebisacrylamide and 160mg of tetramethylethylenediamine were added and 40mg of ammonium persulfate, after mixing evenly, pour it into a pre-laid container made of porous nickel foam as an electrode, seal it and have a cross-linking reaction at room temperature, take out the cross-linked gel after 1h, and put it under nitrogen Soak in saturated distilled water for 24 hours to wash away unreacted components to obtain a soft and elastic carbon nanotube / polyacrylamide gel composite material. After taking it out, the electrode is trimmed to prepare a humidity sensor device.

[0028] The resistivity when it is wet and saturated is 31500Ωcm...

Embodiment 2

[0030]Weigh 3.2 grams of conductive carbon black and 8 grams of monomeric acrylic acid, add 30 ml of water and 0.1 gram of surfactant sodium lauryl sulfate after mixing, stir evenly and put it into an ultrasonic oscillator to vibrate for 2 hours to achieve uniform mixing. At room temperature, after adding 0.2 grams of N, N methylenebisacrylamide, 0.4 grams of potassium persulfate and 0.4 grams of sodium sulfite, pour it into a cylindrical mold with a nickel sheet at one end and lead wires as electrodes. In the process, seal the mold with the other end of the same electrode, and then put it in an 80°C water bath to react for 120 minutes; after the reaction, take out the shaped gel composite material and trim the electrode to obtain a conductive hydrogel composite material and devices.

[0031] Its resistivity in the wet state is 25000Ωcm, and the resistivity in the dry state is 100Ωcm, which is 250 times lower, which is closely related to the close connection of the conductive ...

Embodiment 3

[0033] Weigh 20 g of polyvinyl alcohol (PVA) (polymerization degree 1750, alcoholysis degree 99%), add 160 mL of deionized water, stir and heat up to completely dissolve, add 20 g of conductive carbon black, and cool to room temperature after ultrasonic oscillation for 3 hours; Add 20g of formaldehyde solution with a mass concentration of 37% as a crosslinking agent, 50g of a sulfuric acid solution with a mass concentration of 35% as a catalyst, and 1g of a surfactant. After uniformly stirring in a constant temperature water bath at 35°C, pour it into the prepared In a cylindrical mold with a nickel sheet at one end and a wire drawn out as an electrode, the sealed mold with the other end of the same electrode is cured in an oven at 60 ° C for 4 to 6 hours. Soluble PVA forms water-insoluble polyvinyl formal (PVFM) due to partial cross-linking, with a degree of acetalization of 60%. Take out and wash off unreacted formaldehyde and sulfuric acid, and prepare a black, elastic elect...

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Abstract

The invention discloses a conductive hydrogel composite material which is sensitive to humidity level fluctuation, a device and a preparation method, which relates to a smart material and a device and a preparation method, wherein, the conductive hydrogel composite material and the preparation method thereof comprises four steps of dispersion of conductive filling materials, in situ polymerization, casting to be shaped and electrode trimming; the conductive hydrogel composite material and the device comprise a hydrogel which is sensitive to humidity level fluctuation, the conductive filling materials and an additive. In the process of responding to the environmental moisture change, the obtained conductive hydrogel composite material and the device can make a sensitive response to the external moisture change. The conductive hydrogel composite material and the device can obtain practical applications in the fields of biomedicine, fluid control, diffusion and permeation, intelligent machinery and the like.

Description

technical field [0001] The invention relates to an intelligent material, a device and a preparation method, in particular to a conductive hydrogel composite material sensitive to humidity changes, a device and a preparation method. Background technique [0002] Materials that are highly sensitive to moisture are humidity-sensitive elements, which usually use the changes in physical quantities (geometric dimensions, electrical properties, optical properties, thermal properties) of materials to sense the humidity of the environment during different water content changes. Among them, the hair hygrometer made by the principle of wet expansion and dry shrinkage is simple and convenient, but the size change is small, and auxiliary mechanical amplification devices are needed; Although the humidity sensor prepared by thermal phenomena has high precision, it generally has the disadvantages of expensive equipment and complicated testing. At present, the most widely used is the humidi...

Claims

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Application Information

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IPC IPC(8): G01N19/10G01B7/00
Inventor 曾尤高飞刘鹏飞赵龙赵金波吴文栋黄日勇严丽妮
Owner SHENYANG JIANZHU UNIVERSITY
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