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Cross-sectional observation of a weak boundary layer in polytetrafluoroethylene (PTFE) using scanning electron microscope


A weak boundary layer (WBL), at the surface of polymers, causes poor adhesion, but such a WBL has not been characterized or quantified. In this study, to characterize a WBL of polytetrafluoroethylene (PTFE), we observed a cross-section of PTFE using a scanning electron microscope and compared the surfaces and bulk sides. We observed voids on the surface of the PTFE but not on the bulk side. These voids existed up to 5 µm from the outermost surface of the PTFE. We defined a WBL by the presence or absence of voids and then concluded that the thickness of the WBL in PTFE was of the order of a single micrometer.

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The author would like to thank Enago ( for the English language review.

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YO, KE, and KY supervised the work. YS, MN, and YO performed the washing, cooling, and cutting PTFE sheets. YS performed the SEM observation with MN and YO. All authors contributed to the scientific discussion and manuscript preparation. YS wrote the manuscript.

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Correspondence to Yuji Ohkubo.

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Seto, Y., Nishino, M., Okazaki, Y. et al. Cross-sectional observation of a weak boundary layer in polytetrafluoroethylene (PTFE) using scanning electron microscope. Polym J (2021).

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