Hi Arjun, reduced contact angle may not always mean you have a good adhesion or guarantee good quality films. Are you treating ITO/glass before printing? if so with what? What is / are your ink material? Also coalescence of ink could come from inhomogeneity in the ink itself. Not promising an answer, but bit more information on your systems would help others understand -- plus can you post a photo of the printed film? Thanks, Palash

Hi Arjun, reduced contact angle may not always mean you have a good adhesion or guarantee good quality films. Are you treating ITO/glass before printing? if so with what? What is / are your ink material? Also coalescence of ink could come from inhomogeneity in the ink itself. Not promising an answer, but bit more information on your systems would help others understand -- plus can you post a photo of the printed film? Thanks, Palash

For depositing thin film by printing, two main factors, surface tension and viscosity, influence the uniformity. In your case, the contact angle is 20 degree, which means that the substrate is inkphilic and coffee ring will present. As a result, the film is not uniform. In my opinion, you don't need to reduce the contact angle, instead, to increase contact angle to inkphobic will be favor of depositing uniform film. Moreover, improving viscosity of ink will further suppress the coffee ring and printing uniform film. Thanks, Young.

Thank you Palash Gangopadhyay ,Mike Hambsch, Qiang Yang Sir. I am treating ITO surface with Ozonization. See the attached image with ozone treatment. The attached file is printed film after ozone treatment. I am using aqueous ink with surfactant( for reducing surface tension) for printing having surface tension is ~ 25 mN/m and Viscosity is about 1-2 cP. The substrates temperature is room temperature about 20 degree C.