I have film by using casting dip because spin coating was not give required result, but unfortunately my film was not conductive, after deposited the dispersion of Polyaniline (Emeraldine salt) on glass substrate by casting dip then drying by hot plate and I have done multi layers, the film is not conductive, also I have put some of dispersion Polyaniline ES on Aluminium foil, the area where polyaniline ES was not conductive, What can I do?
Please see the following pictures
Any comment make a sense...
Hi, Islm,
Firstly, to be able to get uniform films by spin-coating from polyaniline solution, you need to treat the substrates either plasma asher or UV ozone to get the surface hydrophilic.
Secondly, you could try different dopants adding into the solution, ideally some solvents such as IPA or ethanol and etc, would be good to help get smooth films and sometimes enhance the film conductivity too.
There are many publications you could find.
Hope it helps.
Xu Wang I used a casting dip technique to coat a film then dry it with heat by using hot plat,
I measured the conductivity by using micro ammeter, If you have different method please tell me.
Thank you
Xuhua Wang I tried plasma cleaner but also after drying the film disappear, I will try to add IPA.
Thank you
Thin film conductivity should be measured using a four-point probe technique. During the processing of your films, you could quickly check using a multimeter to see whether your films are conducting or not. Once you know that your films are conducting, you have to use a four-point probe system to measure the thin film sheet resistance and measure the film thicknesses using a surface profiler such as Bruder Dektak profiler. By knowing the film thickness and sheet resistance, you can obtain the film conductivity. The following link gives you how the four point probe technique works. You could set up your own system if your lab doesn't have such instrument.
https://en.napson.co.jp/technique/
I do agree with Dr. Wang. First make sure that your ES is really conductive by pressing its pellet and measuring the conductivity. If it is around few S/cm it is OK and you have to improve conditions of preparation of the ES dispersion followed by the cast layer (film) formation. If less then you have to find why.
Xu Wang I was use the micro ammeter to measure the ES powder without pressing, but it was not conductive.
The temperature for casting dip was 80 C
why you don't try the electrodeposition? it's easier, controllable and efficient.
I can see that based on your image it's not uniformly deposited if it is not continuous it hard to measure it. In my opinion, you just spray coat on the insulator and just check the surface conductive. if it is conductive then definitely have a problem with your deposition
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