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Flexible Films of Covalent Organic Frameworks with Ultralow Dielectric Constants under High Humidity
Author(s) -
Shao Pengpeng,
Li Jie,
Chen Fan,
Ma Li,
Li Qingbin,
Zhang Mengxi,
Zhou Junwen,
Yin Anxiang,
Feng Xiao,
Wang Bo
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201811250
Subject(s) - dielectric , materials science , polymer , humidity , porosity , alkoxy group , covalent bond , polymerization , composite material , dielectric strength , polymer chemistry , chemical engineering , organic chemistry , optoelectronics , chemistry , alkyl , physics , engineering , thermodynamics
Covalent organic framework (COF) films combine the processability of polymers with the porosity and atomic precision of crystalline porous materials, properties that are long‐sought‐after in electronics yet hard to realize. Herein, we prepared four flexible COF films with different alkoxy side chains via interfacial polymerization. The COF films exhibit an ultralow dielectric constant ( κ =1.19±0.04 at 10 5 Hz), small dielectric loss (<0.02, 10 3 –10 6 Hz), high breakdown voltage (>63 kV cm −1 ) and low leakage current (10 −10 A cm −2 at 1 kV cm −1 ). They have considerable mechanical strength, and ability to withstand high humidity (RH 70 % for 10 days) and repeated bending (1000 times) without losing their dielectric properties. Extension of the alkoxy chains reduces the film's κ and enhances its moisture resistance, while incorporation of guest molecules further increase the κ value up to 43 times.