• Composites Research
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• v.29 no.4
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• pp.173-178
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• 2016

Graphene oxide (GO) was concurrently reduced and functionalized using long alkyl chain dodecyl amine (DA). The DA functionalized GO (DA-G) was assumed to disperse homogenously in linear low density polyethylene (LLDPE). Subsequently, DA-G was used to fabricate DA-G/LLDPE composites by melt mixing technique. Fourier transform infrared spectra analysis was performed to ascertain the simultaneous reduction and functionlization of GO. Field emission scanning electron microscopy analysis was performed to ensure the homogenous distribution and dispersion of DA-G in LLDPE matrix. The enhanced storage modulus value of the composites validates the homogenous dispersion of DA-G and its good interfacial interaction with LLDPE matrix. An increased in tensile strength value by ~ 64% also confirms the generation of good interface between the two constituents, through which efficient load transfer is possible. However, no significant improvement in glass transition temperature was observed. This simple technique of fabricating LLDPE composites following industrially viable melt mixing procedure could be realizable to developed mechanically strong graphene based LLDPE composites for future applications.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.476-476
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• 2011

Introduction of CNTs into a metal matrix has been considered to improve the mechanical properties of the metal matrix. However, the binding energy between metals and pristine CNTs wall is known to be so small that the interfacial slip between CNTs and the matrix occurs at a relatively low external stress. The interfacial strength between CNT and metal matrix is thus one of the key factors for successful development of the CNT/metal composites. Defective or functionalized CNT has been considered to enhance the interfacial strength of nanocomposites. In the present work, we design the various realistic hybrid structures of the single wall CNT/Cu complexes and characterize the interaction between single wall CNTs and Cu nano-particle and Cu13 cluster using first principle calculations. The characteristics of functionalized CNTs with various surface functional groups, such as -COOH, -OH, and -O interacting with Cu are investigated. We found that the binding energy can be enhanced by the surface functional group including oxygen since the oxygen atom can mediate and reinforce the interaction between carbon and Cu. These results strongly support the recent experimental work which suggested the oxygen on the interface playing an important role in the excellent mechanical properties of the CNT/Cu composite.

• Mass Spectrometry Letters
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• v.2 no.2
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• pp.53-56
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• 2011

[ $C_8$ ]functionalized magnetic nanoparticles were synthesized by coating magnetic $Fe_3O_4$ nanoparticles with silicaamine groups using 3-aminopropyltriethoxysilane and by subsequently modifying the amine groups with chloro(dimethyl)octylsilane to produce octyl groups on the surface of the MNPs. The $C_8$-functionalized MNPs were used to enrich peptides from tryptic protein digests of myoglobin and ${\alpha}$-casein. The enriched peptides were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). MALDI-MS was also used to investigate desalting of the $C_8$-functionalized MNPs. Sample solutions were prepared in 1.0 M NaCl, and the successful removal of salt was observed. Enrichment with $C_8$-functionalized MNPs was very effective for separating and concentrating tryptic peptides.

• Macromolecular Research
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• v.14 no.3
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• pp.272-286
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• 2006

Dendritic hyperbranched poly(methyl methacrylate)s (PMMA)s, whose branched architectures resemble the 'dendron' part(s) of dendrimer, were synthesized by an iterative methodology consisting of two reactions in each iteration process: (a) a coupling reaction of u-functionalized, living, anionic PMMA having two tert-butyldimethylsilyloxymethylphenyl(SMP) groups with benzyl bromide(BnBr)-chain-end-functionalized PMMA, and (b) a transformation reaction of the introduced SMP groups into BnBr functionalities. These two reactions, (a) and (b), were repeated three times to afford a series of dendron-like, hyperbranched (PMMA)s up to third generation. Three dendron-like, hyperbranched (PMMA)s different in branched architecture were also synthesized by the same iterative methodology using a low molecular weight, functionalized 1,1-diphenylalkyl anion prepared from sec-BuLi and 1,1-bis(3-tert-butyldime-thylsilyloxymethylphenyl)ethylene in the reaction step (b) in each iterative process. Furthermore, structurally similar, dendron-like, hyperbranched block copolymers could be successfully synthesized by the iterative methodology using $\alpha$-functionalized, living, anionic poly(2-(perfluorobutyl) ethyl methacrylate) (PRfMA) in addition to $\alpha$-functionalized, living PMMA. Accordingly, the resulting block copolymers were comprised of both PMMA and PRfMA segments with different sequential orders. After the block copolymers were cast into films and annealed, their surface structures were characterized by angle-dependent XPS and contact angle measurements. All three samples showed significant segregation and enrichment of PRfMA segments at the surfaces.

• Journal of Adhesion and Interface
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• v.20 no.4
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• pp.146-154
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• 2019

In this study, alkoxysilane-functionalized amphiphilic polymer (AFAP), which have hydrophilic segment and hydrophobic segment functionalized by alkoxysilane group at the same backbone, was synthesized and used as a dispersant and control agent for reaction rate in the preparation of colloidally stable organic-inorganic (O-I) hybrid sols. After reaction with fluorosilane compounds, fluorinated O-I hybrid sols were prepared and coated onto glass substrate to form hydrophobic O-I hybrid coating films through low-temperature curing process. Surface hardness and hydrophobicity of cured coating films were varied with type of solvent and composition of AFAP and fluorinated alkoxysilane compounds. At appropriate solvent and composition of fluorinated alkoxysilane compounds, O-I hybrid coating film having high transparency and surface hardness could be prepared, which could be applicable to cover window of solar cell and displays.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.480.2-480.2
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• 2014

Electrochemical capacitors have been the most strong energy storage devices due to high power density and long cycle stability. Pristine carbon nanotubes are promising electrode materials for excellent electrical conductivity and high specific surface area in electrochemical capacitor. However, the practical application of pristine carbon nanotubes was limited by the aggregation into bundles due to van der Waals force. In this research, we explained how multi-walled carbon nanotubes (MWCNT) functionalized by carboxyl, sulfonic, and amine groups (CNT-COOH, CNT-SO3H, CNT-NH2) to improve the performances of MWCNT. Functionalized CNTs showed two- to four-fold increase in capacitance over that of pristine CNTs, while maintaining reasonable cyclic stability. But, the CNT-COOH showed the lowest rate capability of 57% compared to 84%, 86% of CNT-SO3H and CNT-NH2. As demonstrated by the spectroscopic analysis, This reseach showed how surface functional group of carbon nanotubes change capacitor performances.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.279-282
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• 2012

This study attempted to the effect on the physical performance of silane coupling agent on solventless epoxy-based concrete surface finishing material for parking floor. Tests were carried out in accordance with KS F 4041 and KS F 4937. The results of compressive strength, flexural compressive are 95.6N/㎟, 25.4N/㎟ and after wheel moving load testing, average abrasive depth is 0.96mm, these results satisfied the quality standard of KS F 4041, KS F 4937. As conclusion, this study confirmed that the silane coupling agent greatly effected on the physical performance of solventless epoxy resin.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.29 no.1
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• pp.89-101
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• 2003

A new collolidal silver (Ag) system is present in which a fine colloidal Ag is in situ deposited onto functionalized porous poly(ethylene glycol dimethacrylate) (poly (EGDMA)) microspheres. The effectiveness of Ag deposition was investigated considering the surface characteristics of poly (EGDMA) microspheres, The result reported in this study illustrates that the control of surface area and surface functionality (in this study, a hydroxyl group) of poly (EGDMA) microspheres is an important factor that determines practically the degree of deposition of colloidal Ag. The x-ray analysis showed that Ag nanoparticles were dispersed evenly inner and outer surfaces and has a face center cubic(fcc) phase. In the preservation test, the Ag-containing poly (EGDMA) microspheres had a powerful anti-bacterial performance, showing a high potential for a new preservative.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.33-34
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• 2006

The graft copolymer consisting of poly(N-isopropylacrylamide) (PNIPAAm) and single-stranded DNA was prepared. Interestingly, the copolymer was found to form nanoparticles above physiological temperature. We found that non-crosslinking aggregation of the nanoparticles was induced by the hybridization of the surface-bound DNA with the full-match complementary DNA, but not with one-base mismatch. The core material is not restricted to PNIPAAm; DNA-functionalized gold nanoparticle was found to show a similar aggregation induced only by the fully-complementary DNA, resulting in rapid color change within 3 min at ambient temperature. This methodology is general in principle and applicable for wide variety of clinical gene diagnosis.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1193-1194
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• 2006

The magnetic ferrite nanoparticles were synthesized and coated by silica precursor in controlling the coating thicknesses and sizeses. The surface modification was performed with amino-functionalized organic silanes on silica coated magnetic nanoparticles. The use of functionalized self-assembled magnetic ferrite nanoparticles for nucleic acid separation process give a lot of advantages rather than the conventional silica based process.