Hi Noemi, If your 9% PMMA is currently in chlorobenzene solvent, then it is standard procedure to reduce the viscosity by dilution with chlorobenzene. I'd guess about 3 parts chlorobenzene to 1 part of 9% PMMA will be in the proper range. -Bill Subject: [mems-talk] PMMA dilution in chlorobenzene Dear all, I'm starting to work on PMMA 950K 9%.I'd like to reduce viscosity to operate with a thickness (after spin coating) in the range of 100-200nm.I'd like to know if the procedure of dilution in chloro benzene is a good solution or if it's raccomended to buy a new bottle with proper viscosity.