Polyimide and polytetrafluoroethylene (PTFE) films were examined as alternative materials in heat exchangers in respect of their mechanical behavior at temperatures of up to 90 degrees C and in contact with water, toluene and hexane. It was shown that the PTFE films have a sufficient durability and can be successfully used with these organic liquids. Furthermore, a hydrodynamically optimized prototype of a heat exchanger was designed based on CFD studies coupled with FEM analysis considering geometry deformations of the films caused by pressure loss.