Stretchable silver@CNT-poly(vinyl alcohol) films with efficient electromagnetic shielding prepared by polydopamine functionalization

Abstract

The design of CNT/polymer composite shields is reduced to resolve the issue of CNTs agglomeration which has been tackled by complex and harsh chemical treatments damaging their electrical conductivity and limiting shielding capability. Herein, CNTs were coated with polydopamine (PDA) by exploiting the in-situ spontaneous polymerization of PDA on organic/inorganic surfaces. The PDA functional layer not only resulted in improved CNT dispersion after 2 h-coating time but also served as a platform for subsequent immobilization of silver nanoparticles by the catechol and nitrogen-containing groups of PDA. The well-dispersed CNT and the incorporation of extra silver particles conductive phase resulted in flexible and highly conductive Ag@PDA@CNT-poly(vinyl alcohol) (PVA) films with significantly improved shielding effectiveness of 42.75 dB with respect to pristine CNTs (21 dB). The size of silver particles controlled by PDA polymerization time, the formation of an efficient conductive network and conduction/interfacial polarization-induced loss mechanisms were reasoned to be responsible for dictating the films shielding performance. Such low-key and green approach could be instrumental to developing other metal/CNT polymer films as next-generation lightweight shields for flexible electronics.