Polytetrafluoroethylene(PTFE)is a low-back-ground polymer that is applied to several applications in rare-event detection and underground low-background experiments.PTFE-based electronic substrates are impor-tant for reducing the detection limit of high-purity ger-manium detectors and scintillator calorimeters,which are widely applied in dark matter and 0υββ detection experi-ments.The traditional adhesive bonding method between PTFE and copper is not conducive to working in liquid nitrogen and extremely low-temperature environments.To avoid adhesive bonding,PTFE must be processed for sur-face metallization owing to the mismatch between the PTFE and copper conductive layer.Low-background PTFE matrix composites(m-PTFE)were selected to improve the electrical and mechanical properties of PTFE by introducing SiO2/TiO2 particles.The microstructures,sur-face elements,and electrical properties of PTFE and m-PTFE were characterized and analyzed following ion implantation.PTFE and m-PTFE surfaces were found to be broken,degraded,and cross-linked by ion implantation,resulting in C=C conjugated double bonds,increased sur-face energy,and increased surface roughness.Comparably,the surface roughness,bond strength,and conjugated double bonds of m-PTFE were significantly more intense than those of PTFE.Moreover,the interface bonding the-ory between PTFE and the metal copper foil was analyzed using the direct metallization principle.Therefore,the peel strength of the optimized electronic substrates was higher than that of the industrial standard at extremely low tem-peratures,while maintaining excellent electrical properties.

College of Nuclear Science and Technology,Beijing Normal University,Joint Laboratory of Jinping Ultra-low Radiation Background Measurement of Ministry of Ecology and Environment Beijing Normal University,Key Laboratory of Beam Technology of Ministry of Education,Beijing Normal University,Beijing 100875,China;Beijing Radiation Center,Beijing 100875,China;Department of Engineering Physics,Key Laboratory of Particle and Radiation Imaging of Ministry of Education,Tsinghua University,Beijing 100084,China;Joint Research Center,Nuctech Company Limited,Beijing 100084,China

[1]Shao-Jun Zhang;Yuan-Yuan Liu;Sha-Sha Lv;Jian-Ping Cheng;Bin Liao;Pan Pang;Zhi Deng;Li He-.Surface metallization of PTFE and PTFE composites by ion implantation for low-background electronic substrates in rare-event detection experiments)[J].核技术（英文版）,2022(07):104-114

manium,calorimeters,Comparably

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