Polyimides are a class of polymers with imide rings in their main chains. They
are renowned for their exceptional mechanical properties, high-temperature
resistance, low-temperature endurance, and resistance to chemical solvents,
which allow for long-term use under harsh medical operating conditions.
Consequently, research on polyimide films has garnered widespread attention. In
this study, a two-step method was employed to simplify and optimize the
preparation process of polyimide. Initially, a polyamic acid (PAA) solution was
prepared, and PAA films were fabricated using a spin coater. Subsequently, the
films were imidized to obtain polyimide (PI) films. The impact of various
parameters, such as spinning speed, layer number, and temperature, on the
film-forming properties of polyimide was investigated using the method of
controlling variables. The findings indicate that by setting the spin coater
parameters to 700 revolutions per minute (r/min) for 90 seconds, followed by a
transition to a high speed of 2200 r/min for 210 seconds for spinning the PAA
solution, and then subjecting the film to a temperature gradient of 100°C for 1
hour, 150°C for 1 hour, 200°C for 2 hours, and 300°C for 2 hours for
imidization, a complete and mechanically robust polyimide film can be produced.
The average light transmittance of the film across a wavelength range of
400-2500 nm is 90.46%.