Preferential side chain scission of polytetrafluoroethylene by bending stress

We investigated the chemical composition of polytetrafluoroethylene (PTFE) under bending stress using hard Xray photoelectron spectroscopy and soft X-ray absorption spectroscopy. Our measurements revealed the breaking of C-F bonds in the side chains and conspicuous observation of C-C bonds in the main chain only on the surface under bending stress (carbon-rich). Moreover, we found that the breaking of C-F bonds was dependent on the tensile strain caused by bending. Investigating the effects of tensile and compressive stresses induced by bending, the tensile stress was found to significantly contribute to the breaking of C-F bonds. However, the C-F bonds were hardly broken under uniaxial tensile stress. These findings suggest that tensile stress due to bending, rather than uniaxial tensile stress, causes significant C-F bond scission in the PTFE. This result is attributed to the force acting toward the center of curvature owing to bending, which does not occur under uniaxial tensile stress. Our results provide a better understanding of microscopic PTFE surfaces subjected to flexural tensile stress for nanofluidics and medical engineering applications. Additionally, our findings suggest that carbon-rich structures can be easily fabricated, which may lead to the development of processes for fabrication of two-dimensional materials.

Automated summary

The chemical composition of PTFE under bending stress was investigated using hard X-ray photoelectron spectroscopy and soft X-ray absorption spectroscopy. The breaking of C-F bonds in side chains and the observation of C-C bonds in the main chain were observed only on the surface under bending stress. The breaking of C-F bonds was found to be dependent on the tensile strain caused by bending.