Characterization and tribological properties of two polyimide thin films sputtered onto a copper substrate

Abstract

Two kinds of polyimide (PI), pyromellitic dianhydride-oxydianiline (PMDA-ODA) and biphenyl dianhydride-p-phenylene diamine (BPDA-PDA), thin films were sputtered onto a copper substrate by conventional RF sputtering with argon. These PI thin films were characterized, and their adhesion and tribological properties were evaluated. Elemental compositions and chemical bonding states of these thin films were analyzed with X-ray photoelectron spectroscopy (XPS). Oxygen and nitrogen concentrations in these thin films were less than those in bulk PIs. In addition, the amounts of C O and C N moieties in these PI thin films decreased as compared to the bulk PIs. Contact angles of water and methylene iodide on these PI thin films were higher than those on the bulk PIs. Surface energies of these PI thin films were calculated by measuring contact angles of water and methylene iodide. Surface energies of these PI thin films were lower than those of the bulk PIs and the polar components of these PI thin films were one-third of those of the bulk PIs. Friction coefficients of these thin films were almost the same as those of the bulk PIs. The abrasion durability of PMDA-ODA thin film was higher than that of BPDA-PDA thin film. The adhesion strength between the PMDA-ODA thin film and copper substrate was also higher than that between BPDA-PDA thin film and copper substrate.

Adhesion and Tribological Properties of Sputtered Polymer Thin Films with Thermally Stable Polymer Targets

“…In particular, the polar components of these PI thinˆlms dramatically decrease. This result coincides with the result that extents of C-N and C-O groups which generate polar moieties, such as C-NH and C-OH, in the PI thinˆlms decreased compared to those in the bulk PIs 11) .…”

“…10 (a) and (b) show C(1s)XPS spectrum of the bulk Upilex-S TM and its thinˆlm. The area of the peak2, which contains C-N or C-O moieties, decreased considerably, but that of the peak3, which contains C＝O moiety, is almost at the same level as those of bulk PIs from the results of XPS analyses 11) . It was reported earlier that the nitrogen atom in the imide moiety and the oxygen atom in the ether moiety in the PI structure easily reacted with radicals 12) .…”

“…In order to investigate more detail about the sputtered PTFE thinˆlms, we prepared these thinˆlms at various conditions 9) . Figure 5 shows a schematic diagram of the sputtering apparatus.…”

Intrinsically UV-Resistant Copolyimide: Exploring the Impact of UV-Absorbing Groups on Degradation and Comprehensive Performance

“…Contact angles of water and methylene iodide on PI-A films before and after UV exposure are listed in Table 3. The relationship between surface free energies of the solid (γ S ), the liquid (γ L ), the interface between the solid and liquid (γ SL ), and contact angle (θ) can be represented as follows 42 = + •cos…”

Friction behavior of nano-textured polyimide surfaces measured by AFM colloidal probe

“…Polyimide (PI) deserves special attention in the automotive, aeronautical, and railway transport areas due to its excellent chemical stability, thermal stability and mechanical properties [23,24]. Li group synthesized the PI/silica (PI/SiO 2 ) hybrids with different size of silica by using sol-gel method, and investigated the effect of silica size on the friction behaviour of PI hybrids through a ball-on-disc wear tester under dry sliding conditions [25].…”