Effect of ageing of a polyamido acid solution and the conditions of its imidisation on the structure and properties of thin polyimide films

摘要

Thin films with a thickness of the order of several micrometres of thermally stable and heat resistant aromatic polyimides (PIs) with fairly high deformation and strength properties and low gas and water vapour permeability are used effectively in the production of miniature actuators and transducers (sensors) of microsystem technology (micromechanics and microsensors).The most widely used methods for producing such films are based on flow of unstable solutions of polyamido acid (PAA) solutions or their derivatives in strongly polar solvents on a solid surface,drying of the solutions,thermal imidisation of PAA,and separation of the film from the substrate.The production of films is accompanied with complex physical and chemical processes of structure and defect formation on the molecular,supermolecular,and macroscopic levels.