Morphology and Mechanical Properties of Polyimide Films: The Effects of UV Irradiation on Microscale Surface

Abstract

As an attractive dielectric material, polyimide has been widely used in the field of electronics, aerospace, and automobiles due to its useful mechanical properties and good chemical resistance. UV irradiation was considered to be the main factor related to the damage and failure of polyimide. Here the effects of UV irradiation on the surface morphology and microscale mechanical properties of polyimide films are characterized by atomic force microscopy (AFM). The surface roughness of the UV-irradiated samples developed and the mechanical properties degraded with the radiation dose increased. For comparison, uniaxial tensile test was performed to obtain the macroscale Young’s modulus of polyimide film. The UV-irradiated damaging depth was simulated with finite element method (FEM).

Fabrication of UV Laser-Induced Porous Graphene Patterns with Nanospheres and Their Optical and Electrical Characteristics

“…Although the absorption rate varies depending on the fluence of the laser, it has an absorption rate of over 85% from very low fluence of 10 mJ/cm 2 [ 25 ]. There have been many studies on the processing of polyimide, using UV lasers [ 26 , 27 ].…”

Review of Radiation-Induced Effects in Polyimide

“…Severe degradation of PI surface roughness with formation of humps and dents with~20 nm height/depth, respectively, as a result of PI film exposure to the UV irradiation in a form of single UV-laser pulses with pulse durations between 140 ns and 5 µs was reported [16,153].…”

“…Sufficient electronic energy deposition will also rupture bonds, but the damage will be deposited over a longer trajectory and the chemical damage will be more bond-selective. UV photons are energetic enough to dissociate molecular bonds, resulting in photo-oxidation reactions that scissor or crosslink the polymer chains [16]. Indeed, even very low energy ions and low mass particles such as He + ions impart enough energy to break all bonds along a penetration track in principle, but experimental studies have shown that low energy and low mass particles impart damage through distinct and relatively well defined reactions [17].…”

Sandwiched polyimide‐composite separator for lithium‐ion batteries via electrospinning and electrospraying

“…[9] Polyimide (PI) has been used for LIB separators by utilizing poly(amic acid) ammonium salt (PAAS) as a prepolymer of PI, as shown in our previous study. [10] PI has excellent thermal, mechanical, and electrochemical properties, [11][12][13] and its polar groups can improve the electrolyte wettability. [14,15] The thermal stability and mechanical properties of PI separators can be improved by loading inorganic nanoparticles into PI matrix.…”