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Youngnam Kim (1,2), Ki-Ho Nam (1), Yong Chae Jung (2), Haksoo Han (1)
Composites Part B, 203, October 2020. DOI: 10.1016/j.compositesb.2020.108451
Multi-stimuli responsive, Self-healing, Interfacial adhesion, Bilayer polymer structure,Microencapsulation
Simple self-healing behavior of polymers that respond to multiple physicochemical stimuli are highly desirable for industrial applications. In this study, under various external environmental stimulating factors, we focus on the self-healing kinetics of polymer bilayer films (PBFs) comprising a colorless polyimide (CPI) bottom-substrate layer and linseed oil loaded microcapsule (LOMC)-embedded polydimethylsiloxane (PDMS) upper-healing layer. The experimental results showed clear correlation between stimulating factors and the healing time. Although the crack-healing behavior of PBF with 5 wt% microcapsule under air atmosphere is fairly slow, it has an improved healing effect at the artificial crack interface heating to 70 °C; moreover, gradual healing is observed by moisture absorption in environments with relative humidity of 70%. Remarkably, we found that ultraviolet (UV)-light irradiation through the 5 wt% LOMC-filled PDMS layer triggers a noticeable kinematic advantage for the drying reaction that initiates interfacial self-healing. Short-time (20 min) UV-irradiated PBF 5 wt% exhibits a low water vapor permeability of 35.4 g m−2 day−1 and excellent healability with ~91% recovery by single capsule-type photochemical-induced self-healing. The proposed approach advances the extrinsic healing of colorless polymers in a kinetically effective way without compromising their chemical composition.
Dragonfly was used for 3D image reconstruction.
(1) Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea.
(2) Institute of Advanced Composites Materials, Korea Institute of Science and Technology, Chudong-ro 92, Bondong-eup, Wanju-gun, Jeollabuk-do, 565-905, Republic of Korea.
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