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P-915 : Controlled Anisotropic Dewetting with SAMs
장세규,양승만 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.2
Polymeric nano- and micro-scale structures are very useful for many applications such as optics, bio-sensing, and catalysis, etc. Especially, self-assembly of polymer is simple and low cost process to make valid structures. For decades, polymer dewetting has been investigated because of its importance for coating industry. However, recent researches have focused on the creating of useful pattern with many polymers. Several years ago, Lee et al introduced the phenomena of anisotropic dewetting which is dewetting of polymer thin film in the channel. They showed that thin polymer films in the channel above Tg, deformed into mountain-shape due to capillary force between side wall and polymer.Then, sufficient heating duration can stimulate the capillary instability and dewetting of polymer in channel will be initiated. By using this phenomena, isolated polymer lines can be obtained with large area. However, these lines are randomly arranged and have little use. It ! is because of property of self-assembly. This nature of anisotropic dewetting should be controlled to be used for applications. In our work, we controlled the arrangement of anisotropic dewetting structure with heterogeneous pattern of SAMs and different surface property of patterned substrate is enough to lead the ordered dewetting of PS thin film.
Fabrication of Ultrafiltration Membrane for Micro-dust Removal using Boron Nitride Nanotubes
장세규 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Boron nitride nanotubes (BNNT) are drawing attention due to their unique physical properties over carbon nanotubes such as high oxidation resistance (stable up to 900°C), piezoelectric, and high neutron absorptivity. However, the nano-dispersion of BNNTs especially in organic solvents, which should be achieved for fabrication of composites with reproducible properties, has still been a challenging issue. In this talk, we will present a non-covalent functionalization approach using poly(4-vinylpyridine) (P4VP) in order to efficiently debundle and achieve nano-dispersion of BNNTs in various protic solvents without any damages on physical properties of BNNTs. By taking advantages of the highly debundled BNNT dispersion, thermally regenerable ultrafiltration membranes which can exclude higher than 99.9% of nanoparticles (about 25 nm in diameter) as well as environmental nano-dusts were fabricated.
Boron Nitride Nanotube Liquid Crystals: Preparation, Characterization, and Application
Se Gyu Jang(장세규),임홍진,김영경 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2
Boron nitride nanotubes (BNNTs) have been considered as an emerging nanomaterial owing to their superb physical properties such as high specific mechanical strength, high thermal conductivity, high oxidation resistance (stable up to 900 ℃), piezoelectric, and high neutron absorptivity. However, the high concentration BNNT dispersion, which should be achieved to maximize the advantages of BNNTs in composite applications, has still been a challenging issue. In this talk, we will present a non-covalent functionalization approach in order to efficiently disperse BNNTs in water. Interestingly, a lyotropic BNNT liquid crystal (LC) was observed at a critical concentration of BNNTs. The BNNT LCs were characterized by polarized optical microscopy (POM) and their rheological properties were investigated systematically. Finally, by wet-spinning of the BNNT LCs, a BNNT/polymer composite fiber composed of unidirectionally aligned BNNTs inside the fiber was fabricated.