Casting polymer films by high volatile solvent evaporation - Practical method to avoid bubbles (Mar/03/2009 )

Dear all,

I need a little bit of advice as i am trying to find an efficient method to cast polymer films with a constant thickness by volatile solvent evaporation.

I am struggling as for the films to have constant thickness, I need just prior casting to measure the amount of polymer (which is diluted in a high volatile solvent). But this step gives me already trouble as during the process 1) bubbles for with contact with air 2) lost of polymer solution in the measurement container as the cocktail is quite viscous.

Thus, I was wondering somebody could share his/her practical tips for this normally easy step. (container, equipment he/she used)

thanks a million times for any help and advice

enguyen

No magic. Visicous is a part of polymer property, esp. when the MW is high. As far as bubble problem, youjust have to stir it slowly and put it in a closed container over time to disslove it slowly to reduce bubble trapped within. If you load it to a syringer I think it will help you to dispens the fixed amount to your surface.

I hope these practical tricks help.

You might try a vacuum to expand bubbles, making them easier to remove. I don't know how well this would work with a volatile solvent, however.

thank you all for these tips.

also to reduce the viscosity problem, I thought about simply dilute more the polymer. it will increase i guess the evaporation process, but at least i can be more precise with the polymer amount that ill be pouring.