Best Polymers for Humidity Sensing

[Kamal_]

I am working on a capacitive humidity sensor, using polymer as a dielectric between two electrodes, does anybody know which polymer would react best to water vapor or water moisture or Rh (Relative Humidity)?

 

[Compositepro]

Cellophane is best. Nylon would also work.

 

[Kamal_]

Thank you! Would cellophane detect full range of relative humidity from 0% to 100%?

 

[Compositepro]

I believe if cellophane is exposed to 100% humidity it will can swell so much that will not return to the same dimensions when dry. It depends on the temperature.

 

[IRstuff]

Unless this is for a school project, it seems to me to be a hobby post.

Digikey lists 643 humidity sensors; can't see the world needing yet another one.

https://www.digikey.com/products/en...tity=0&ColumnSort=1000011&page=1&pageSize=500

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[Kamal_]

Thanks for your reply. if Cellophane will at 100% Rh, swell and may not come back to its original position, or the reaction time will be very slow, it will not work in my application. , so what do you suggest? Do you have any other suggestions?

 

[IRstuff]

You could just buy one; the cost to design, build, and calibrate one would be orders of magnitude more than

From Digikey

https://www.digikey.com/product-detail/en/neptune-control/RH101-A/2461-RH101-A-ND/11684998

$22 with ±1% accuracy, which is already less than the engineering time it took to find it.

Or this

https://www.digikey.com/product-detail/en/sensirion-ag/SHT35-DIS-F2-5KS/1649-1067-2-ND/6212135

at $5.29, but ±1.5% accuracy

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[Kamal_]

Thanks for your reply, we are not hobbyists' and this is not a hobby project for us, we are serious in designing the sensor that will work better than your suggested Sensirion part from Digikey. We have designed the sensors and the probe to read the capacitive sensor with success and we are looking to have expert suggestions to improve our design. If you can suggest your ideas we highly appreciate. Please let us know if you can help.

 

[3DDave]

Work better in what way?

 

[IRstuff]

we are serious in designing the sensor that will work better than your suggested Sensirion part from Digikey. We have designed the sensors and the probe to read the capacitive sensor with success and we are looking to have expert suggestions to improve our design.

You claim to not be hobbyists, and are therefore likely to be students, who are forbidden from posting their coursework questions on this site. A company cannot possibly contemplate designing a "better" humidity sensor and have not even done basic research into dielectrics. Even a cursory literature or patent search would have resulted in a better starting question.

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[karthik.kb028]

How long we can store ABS in natural way?

 

[BrianPetersen]

Decades.

I have a 32 year old motorcycle whose original-equipment ABS fairings are still in fine shape.

More details = better answers.

 

[IRstuff]

What doesn't keep are the asinine coatings they put on to some tools that turn into goop after a year or so; I don't know if it base material was ABS or something else, but the goo is sticky and annoying

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[BudgetMoldKing]

Karthik To answer your question on the storage time on ABS.

For quality retainment purposes it recommended storing ABS no longer than 3 to 5 years.


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