Dear Shyam kishor Sharma , PTFE can withstand really high temperatures, so I wonder how much did you heat your film to degrade it. Most PTFE coatings are cured at temperatures between 380-420ºC in an oven, and these conditions can cause oxidation of copper, which develops an oxide layer that causes poor or not adhesion at all of the PTFE. Working in a controlled atmosphere could help, as also does application of a thin layer of electroless nickel as described in the following link:

http://www.ptfecoatings.com/applications.php

You also could have a look to this former thread on RG:

https://www.researchgate.net/post/Could_Teflon_be_coated_on_copper

There are some formulations of PTFE that could be cured at low temperatures (80ºc or room temp) and that could work for your copper tape.

https://www.surfacefinishing.com/doc/low-temperature-thin-surface-coating-0001

Hope it helps.

Most thin film coatings are not PTFE, but rather FEP fluorinated ethylene-propylene (called Teflon FEP). You can look for powder coating grades of the material. Even easier is CTFE (called Halar). Again look for powder coating grades

Thanks for answers, I am using PTFE dispersion (60 wt% dispersion in water) purchased from sigma Aldrich (product code 665800-100ML) .I just drop casting it on copper tape and then dry it on hot plate at 120o C for 2 hr, but what happen after drying the water evaporated but there in not formed PTFE thin film on copper tape even only power form remain which easily eroded on touch. I want a thin film of PTFE on cupper electrode. Please give me suitable suggestions Manuel Gómez

thanks

Dear Shyam kishor Sharma , the PTFE preparation you are using is a water disperion of tiny particles of PTFE (typical particle size around 200nm). PTFE is non soluble in water, therefore non-ionic surfactants are used to mantain PTFE particles in water suspension.

From:

https://www.polysciences.com/default/poly-teflon-30b

The water can be removed at 120°C; wetting agents (surfactants) at 270°C; and melted above 337°C. PTFE will retain its properties up to 260°C.

So, you are only at the first stage, removing water at 120ºC, and this explains your poor results. After removing water, what you have is just PTFE particles coated or mixed with surfactants. They are like pouder, a single stroke will remove some of them leaving a traze or mark in the powder film.

You need to heat your powder film above 270ºC to remove the surfactants and above 337ºC to melt the PTFE and get a continous thin film.

Remember that copper can be oxidized and that will cause poor or null adhesion of the PTFE. Also any grease or dirt will cause no adhesión as clearle stated here:

https://www.fluoroprecision.co.uk/materials-coated/ptfe-coated-copper-and-brass.

Take into account the recomendation of Barry Arkles as alternative solution.

Also you could buy teflon coated copper tape, if this is not the pourpose of your research.

Hope it helps.

Thanks for your suggestions ,I will try it.

I not find taflon coated copper tape online for buy.Is it available?

Dear Manuel Gómez , thanks for your response but as you suggested I put PTFE powder in oven at 337o C for 1 hr but there is now thin film form even PTFE Powder not melted.

ask for PFA dispersion samples from Dupont or Daikin，tell them you are doing a very big business and request their technology surpport.

plasma polymerisation of perfluoromonomer will produce PTFE-like film with good adhesion.