정종문 교수

Abstract The electrical repair of device circuits has been considered a main issue in the area of electronic packaging. Demand for self‐healing conductors as cost‐effective and promising materials for prolonging the durability of devices has increased. Recently, diverse designs of self‐healing and deformable circuits have been introduced in virtue of their high stretchability and conductivity. However, encapsulating a liquid metal with a polymer in a micro‐size container is essential for real ap

Cinnamide moiety-containing polydimethylsiloxane (CA-PDMS) was prepared and used as a healing agent. The photo-cross-linking behavior of CA-PDMS was investigated by UV-vis and Fourier transform infrared (FT-IR) spectroscopy. Upon photo-irradiation, CA-PDMS generates viscoelastic substances which have intrinsic recoating (or self-healing) capability when scribed with a cutter blade. CA-PDMS was microencapsulated with a urea-formaldehyde polymer, and the mean diameter and size distribution of the

ABSTRACT Conventional synthesis of polyimides includes high‐temperature (160–350 °C) imidization of poly(amic acid)s. In the present work, imidization has been carried out at much lower temperatures (40–160 °C). 1,2,4,5,‐cyclohexanetetracarboxylic dianhydride (HPMDA) or pyromellitic dianhydride (PMDA) was polymerized with an aromatic diamine, 4,4′‐diaminodiphenylmethane (DDPM), to give poly(amic acid)s, which were then imidized chemically. Imidization was more than 90% complete even at the very

1,1,1-Tris[4-(2'-hydroxy-3'-methacryloyloxypropoxy)phenyl]ethane (THMPE) and tris[4-(2'-hydroxy-3'-methacryloyloxypropoxy)phenyl]methane (THMPM) were synthesized and evaluated as base monomers in a dental composite system. The photopolymerization reactivity of the trifunctional methacrylates was similar to that of conventional 2,2-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)phenyl]propane (bis-GMA). Of the three monomers (THMPE, THMPM, and bis-GMA), THMPE has the greatest molecular volume, and

Low-temperature self-healing capabilities are essential for self-healing materials exposed to cold environments. Although low-temperature self-healing concepts have been proposed, there has been no report of a microcapsule-type low-temperature self-healing system wherein the healing ability was demonstrated at low temperature. In this work, low-temperature self-healing of a microcapsule-type protective coating was demonstrated. This system employed silanol-terminated polydimethylsiloxane (STP) a

Linseed oil undergoes an oxidative drying reaction upon exposure to air, resulting in a soft film. The reaction conversion after 48 h reached 88% and 59% when it reacted at room temperature and −20 °C, respectively. Linseed-oil-loaded microcapsules were prepared using a urea-formaldehyde polymer as the shell wall material. The microcapsules were integrated into a commercially available protective coating formulation to prepare self-healing coating formulations with different capsule loadings. Th

The structure-property relationship of partially aliphatic copolyimides has been studied for the development of flexible, transparent polyimide films. A structurally rigid cycloaliphatic dianhydride and three aromatic dianhydrides having different structural flexibility were reacted with 4,4′-oxydianiline to prepare the copolyimides. In order to control the balance between aromaticity and aliphaticity and between rigidity and flexibility of the copolyimides, the molar ratio of the dianhydrides w

A microcapsule-type self-healing protective coating with secondary crack preventing capability has been developed using a silanol-terminated polydimethylsiloxane (STP)/dibutyltin dilaurate (DD) healing agent. STP undergoes condensation reaction in the presence of DD to give a viscoelastic substance. STP- and DD-containing microcapsules were prepared by in-situ polymerization and interfacial polymerization methods, respectively. The microcapsules were characterized by Fourier-transform infrared (

Generally, microcapsule-based self-healing materials have the limitation of single local self-healing. A few studies have reported repeatable self-healing in these microcapsular materials, but there is a challenge to develop multi-cycle self-healing materials that have the advantages of easier preparation and a more efficient operation. In this work, a mixture of two vegetable oils, soybean and olive oil, was used as a healing agent. The atmospheric oxygen-induced reaction behavior (in the prese

Despite significant medical benefits as in space exploration or emergency care, prolonged torpidity of non-hibernator mammals remains unexplored to date. Here, we report that male Institute of Cancer Research mice could sustain two separate 2-day torpor bouts and maintain body temperature of 28-33°C following repeated treatments of 3-iodothyronamine (T(1) AM), a natural derivative of thyroid hormone. A 1-day interbout arousal period, adopted to mimic the behavior of true hibernators, seemed crit