Korea Advanced Institute of Science and Technology · Materials Science
Professor Sang Youl Kim's research lab specializes in the design and synthesis of advanced functional polymers with tailored optical, thermal, and mechanical properties for next-generation electronic and separation applications. Key research directions include developing high-performance polyimides and poly(amide-imide) materials for transparent and flexible displays, engineering supramolecular architectures using primary amides and liquid crystalline ligands for nanostructured materials, and creating hyperbranched polymers and porous films with precise nano- and micro-patterning for gas separation and sensing. The lab integrates molecular design with materials processing to achieve materials with exceptional thermal stability, transparency, and tunable surface properties.
Figures are computed from collected data and may differ slightly.
The key component currently missing for the next generation of transparent and flexible displays is a high-performance polymer material that is flexible, while showing optical and thermal properties of glass. It must be transparent to visible light and show a low coefficient of thermal expansion (CTE). While specialty plastics such as aromatic polyimides are promising, reducing their CTE and improving transparency simultaneously proved challenging, with increasing coloration the main problem to
Spontaneous one dimensional arrangements of spherical Au nanoparticles were accomplished by using a liquid crystalline thiol ligand, 4'-(12-mercaptododecyloxy)biphenyl-4-carbonitrile. Simple thermal treatment of Au nanoparticles with the ligands showed 1D ordering of the Au nanoparticles.
A line-patterned breath figure film is achieved using a photo-crosslinkable small molecule through a novel dual-patterning process that combines a breath-figure technique (bottom-up) and photolithography (top-down). The organogelator molecules form honeycomb structures, organizing into supramolecular fibers similar to polymers that stabilize water droplets.
The effects of incorporation of fluorinated alkyl side groups into polyimide membranes were investigated in terms of their physical and gas permeation properties. Four polyimides with fluorinated side groups and four polyimides without the side groups were prepared by polycondensation of 2-(perfluorohexyl)ethyl-3, 5-diamino benzoate (PFDAB) and m-PDA with four aromatic dianhydrides (6FDA, ODPA, BTDA, and PMDA), respectively. It was found that the incorporation of fluorinated side groups into the
Primary amides are unique supramolecular synthons possessing two hydrogen donors and two hydrogen acceptors. By interacting in a complementary fashion, primary amides reliably generate two-dimensional hydrogen bonded networks that differ from conventional hydrogen bonded structures such as carboxylic acid dimers or one-dimensional secondary amide chains. This feature permits the design of sophisticated supramolecular assemblies based on primary amides (especially aromatic amides). Several intere
Abstract Summary: New hyperbranched poly(arylene ether amides) with fluorine or hydroxy end groups were synthesized from AB 2 or A 2 B type monomers via a nucleophilic aromatic substitution (S N Ar) reaction. Monomer syntheses were facilitated by chemo‐selective amidation reactions, and even a direct synthesis of hyperbranched polymer was possible without isolation of the monomer. The resulting hyperbranched poly(arylene ether amides) showed highly branched characteristics (DB = 0.43–0.53), high
New poly(arylene ether amide)s with trifluoromethyl pendent groups were prepared via nucleophilic nitro displacement reaction of AB-type monomers. 4-Nitro-3-trifluoromethyl-[N-(4-hydroxyphenyl)]benzamide (3) and 4-nitro-3-trifluoro-methyl-[N-(3-hydroxyphenyl)]benzamide (4) gave polymers with weight-average molecular weights over 42 000 g/mol and glass transition temperatures of 269°C and 213°C, respectively. Both polymers were soluble in common organic solvents including THF, and formed transpar
Abstract A new hyperbranched poly(phenylene oxide) was synthesized from a simple AB 2 type monomer, 3,5‐dibromophenol, by Ullmann polycondensation. The bromo‐terminated hyperbranched poly(phenylene oxide) was amorphous ( T g = 120 °C), but showed high thermal stability ( T 5d = 480 °C in nitrogen). The polymer with the degree of branching of 0.61 showed good solubility in organic solvents. The highly branched nature of the polymer effectively disrupted the crystalline characteristics of the line
Abstract Well‐defined trifluoromethylated poly(phenylene oxide)s were synthesized via nucleophilic aromatic substitution (S N Ar) reaction by a chain‐growth polymerization manner. Polymerization of potassium 4‐fluoro‐3‐(trifluoromethyl)phenolate in the presence of an appropriate initiator yielded polymers with molecular weights of ∼4000 and polydispersity indices of <1.2, which were characterized by 1 H nuclear magnetic resonance spectroscopy and gel permeation chromatography. Initiating site
The construction of azide-bearing polymeric networks using a dipolarophile and a diisocyanate.
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