CleviousTM PEDOT:PSS PH1000 is a highly conductive polymer. I need to spin coat it on PET substrate. When I place a drop of the solution on my substrate, it is forming some bubble with large contacts angle and as the spinning starts, it is spreading away from the substrate.
Please suggest methods to form a uniform layer of it.
Thanks,
Hi Sai,
You may try by mixing your PEDOT:PSS solution with the fluorosurfactant Zonyl before spin-coating. Details of the solution preparation you may find in the article linked below:
1. Article Facile Optimization of Thermoelectric Properties in PEDOT:PS...
Sincerely,
Anjani
PEDOT:PSS is polar and PET is nonpolar. Hence the problem.
You can obtain good films by making the substrate polar i.e., by increasing its wettability. This will also decrease the contact angle. This could be accomplished in many ways.
One way is by incorporating oxygen into the polymeric chains and making them polar i.e. by oxidation. This can be done by ozone treatment, UV treatment etc.
add any surfactant with pedot:pss or do ozone treatment of the pet substrate.
you can find in the given link:https://www.researchgate.net/post/How_can_one_prepare_PEDOTPSS_films_on_flexible_PET_substrates_that_are_hard_to_peel_off
techniques to enhance the pedot:pss film adhesion on pet substrates. The main problem is that pet surface is very passive and saturated and must be either chemically or physically activated.
Best wishes
There are usually two methods used to form a uniform layer of PEDOT:PSS on a substrate. Although my answer applies to Si-substrate, it can be extended to other substrates. The second method is very general. You first need to find whether the substrate is hydrophilic or hydrophobic. Once you know, you can easily proceed.
1. Since PEDOT:PSS (a water rich polymer) does not form a good and uniform film on silicon (which is hydrophobic), you must implement a very thin layer of silicon dioxide layer (1-3nm)- using HNO3 oxidation, native oxide or plasma oxidation- to make silicon surface hydrophilic. Oxide layer helps making silicon surface hydrophilic .This means, any substrate has to be hydrophilic.
2. If you don't consider forming any type of oxide layers, you must use surfactants (such as Zonyl, Triton) mixed with PEDOT:PSS to reduce the surface tension of PEDOT:PSS liquid. In this case, PEDOT:PSS will spread over even hydrophobic surface of silicon (or any substrate) and will result a uniform film after spin coating.
All of the above recommendations are very useful. I tried triton x100.
Thank you all,
Can you suggest some surfactants which are cleanroom compatible? I need to do the further process in class 100 cleanroom.
Dear Sai
As other researchers mentioned, Triton X-100 and 2-propanol are suitable to reduce its surface tension. Further, plasma treatment is more effective that UV or ozone treatment.
Best
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