Investigation on the microstructural and mechanical properties of a Polytetrafluoroethylene thin film by radio frequency magnetron sputtering

1High-quality Polytetrafluoroethylene thin films prepared by magnetron sputtering.2Deposition power increased, film density increased, surface roughness decreased.3Hydrophobicity performance of films enhance with decreasing deposition power.4Greatly enhanced mechanical properties compared with its bulk counterpart. Relying on magnetron sputtering technology, a Polytetrafluoroethylene (PTFE) thin film was deposited on silicon substrate. We systematically investigated the atomic bonding, growth mode, and surface morphology of the as-prepared PTFE thin films by different nominal deposition power with different thicknesses. The mechanical properties including elastic modulus, hardness, strain rate sensitivity and creep resistance were carefully detected in a thick (1270 nm) PTFE film by an instrumental nanoindentation. In comparison to its bulk counterpart, PTFE thin film owns much higher elastic modulus and stronger resistances to the plastic and time-dependent plastic deformation. The results of its chemistry and mechanical properties show the films are hydrophobic and of higher mechanical strength. The enhanced mechanical properties of PTFE thin film could be intrinsically tied to its complex fluorocarbon groups which generated from the breakage and re-organization of C-F chains during sputtering process. The creep resistance of PTFE thin film was approximately two times stronger than the bulk PTFE.