• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2921-2926
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• 2009

Cu-BTC[$Cu_3(BTC)_2(H_2O)_3$, BTC = 1,3,5-benzenetricarboxylate], one of the most well-known metal-organic framework materials (MOF), has been synthesized under atmospheric pressure and room temperature by using ultrasound. The Cu-BTC can be obtained in 1 min in the presence of DMF (N,N-dimethylformamide), suggesting the possibility of continuous production of Cu-BTC. Moreover, the surface area and pore volume show that the concentration of DMF is important for the synthesis of Cu-BTC having high porosity. The morphology and phase also depend on the concentration of DMF : Cu-BTC cannot be obtained at room temperature in the absence of DMF and aggregated Cu-BTC (with low surface area) is produced in the presence of high concentration of DMF. It seems that the deprotonation of benzenetricarboxylic acid by base (such as DMF) is inevitable for the room temperature syntheses.

• Bulletin of the Korean Chemical Society
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• 제27권1호
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• pp.53-58
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• 2006

A powder of destructive adsorbent was prepared by impregnating Mn and Cu on the surface of amorphous aluminosilicate. It catalytically dimerized tert-butyl mercaptan into di-tert-butyl disulfide on its surface. Turnover of the dimerization was strongly dependent on the surface morphology of the adsorbent, which could be altered by modification of aluminosilicate support. During the process of impregnation, which involved heat treatment at 500 ${^{\circ}C}$, the shape of the pore was preserved, though large fraction of micropores were eliminated. The reactive sites on the surface were poisoned as dimerization products strongly adhered on them. Therefore, high surface area was not always desirable. When the surface was heavily populated with “inkbottled” pores with a narrow entrance in uniform size, heavy poisoning of the reactive sites turned the destructive adsorbents almost useless.

• Bulletin of the Korean Chemical Society
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• 제22권9호
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• pp.948-952
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• 2001

Periodic mesoporous organosilicas with rope-based morphology from a reaction gel composition of 1 BTME : 0.57 ODTMABr : 2.36 NaOH : 353 H2O were synthesized. While long rope-shaped product dominated in case of static synthesis condition , gyroid type products instead of rope shaped product appeared and rope shaped product disappeared with agitation. PMO with such a long rope shaped morphology is firstly reported. Additionally, various rope-based morphologies depending on the degree of bending, twisting, folding and winding of rope such as spirals, discoids, toroids, and worm-like aggregates were observed. White powdered products were characterized by X-ray diffraction, N2 sorption measurement, SEM and TEM. From XRD pattern and TEM image, ODTMA-PMO with hexagonal symmetry was identified. The pore diameter and BET surface area of ODTMA-PMO are $32.9{\AA}$ and 799 m2g-1 , respectively. Hexagonally arrayed channels run with long axis of rope and rope-based shapes with various degree of curvature, which was elucidated by using TEM images.

• Biomaterials and Biomechanics in Bioengineering
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• 제4권1호
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• pp.1-8
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• 2019

The aim of this study was to investigate the effect of total polymer concentration on the chemical structure, morphology of pores, porosity, swelling ratio, degradation of gelatin-poly (vinyl alcohol) (Gel-PVA) cryogel scaffolds. Porous cryogels were prepared with cryogelation technique by using glutaraldehyde as a crosslinker. Functional group composition of cryogels after crosslinking was investigated by Fourier Transform Infrared (FTIR). The morphology of cryogels was characterized via scanning electron microscopy (SEM) and porosity analysis. All of the cryogels had a porous structure with an average pore size between $45.58{\pm}14.28$ and $50.14{\pm}4.26{\mu}m$. The cryogels were biodegradable and started to degrade in 14 days. As the polymer concentration increased the swelling ratio, the porosity and the degradation rate decreased. Spongy and mechanically stable Gel-PVA cryogels, with tunable properties, can be potential candidates as scaffolds for tissue engineering applications.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.818-819
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• 2006

The effect of individual gas constituents in a sintering atmosphere is examined to optimize the sintered properties of Iron-Carbon P/M components. The influence of sintered properties is reviewed as a function of hydrogen percentages and dew point in the sintering zone. Microstructures, porosity, pore morphology and dimensional changes are the subject of this review. The effects of CO containing atmospheres are compared against the non CO atmospheres in terms of hardness, carbon control and dimensional changes.

• 한국포장학회지
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• 제26권2호
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• pp.77-83
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• 2020

바이오매스가 포함된 발포구조체의 발포온도에 따른 SEM, 밀도, 공극률, 수분투과도 측정을 통해 특성 변화를 분석하였으며, 소비자가 해당 용기를 사용할 때의 열적 안정성을 확인하기 위해 MIL-STD규격에 따라 열충격 처리의 영향을 분석하였다. 측정 결과 발포온도가 증가할수록 대체로 기공의 크기는 증가하고 기공의 수는 감소하여 밀도는 통계적으로 유의한 차이가 없음을 확인하였다. 또한 공극률과 수분투과도 측정결과는 서로 다른 경향성을 보이고 있는데 이는 기공의 크기와 수, 기공 간의 구도가 변화하였기 때문인 것으로 사료되며, 이에 대한 추가적인 연구가 필요하다. 열충격 시험 결과, 열충격 반복횟수를 거듭할수록 기공의 크기가 감소하면서 밀도는 증가하고 공극률과 수분투과도는 감소하는 것을 확인할 수 있었다. 이는 시료에 고온을 가함으로써 시료가 연화되었고, 연화된 상태의 시료에 곧바로 저온을 가하여 시료가 수축되면서 기공의 크기와 구도가 변화하였기 때문인 것으로 판단된다. 하지만 밀도의 경우 통계적으로 유의한 차이가 없었으며 수분투과도의 경우 수치가 감소하는 경향을 확인할 수 있었으므로 해당 발포구조체로 제작된 HMR 용기는 열적 안정성이 있다고 판단할 수 있다.

• 한국산학기술학회논문지
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• 제17권2호
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• pp.58-65
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• 2016

본 연구는 조직공학용 지지체로 사용될 막을 개발하기 위한 초도 연구 수행으로, 염화나트륨(NaCl)을 기공형성체로 혼합한 폴리카프로락톤(PCL)용액을 유리 캐스팅판에 분주한 후 필름 어플리케이터를 이용하여 다공성 PCL필름을 성형하였다. 성형된 필름은 건조 후 증류수에 침지시켜 NaCl을 추출하여 최종 멤브레인형 다공성 지지체를 제조하였다. 3차원 다공망을 형성시키기 위하여 NaCl을 기공형성체로 이용하였으며 $4^{\circ}C$, 실온, $40^{\circ}C$의 세 가지 건조조건에 따른 다공망의 형성과 형태를 주사전자현미경(SEM)을 이용하여 관찰 하였으며 기초적인 안전성 확보를 위한 세포독성평가를 시행하였다. 세 가지의 건조조건별 결과에서는 실온 건조조건에서 거대기공과 미세기공이 혼재된 3차원 다공망이 우수하게 형성된 것이 관찰되었으며 세포독성 시험결과 ISO10993-5 규격의 세포독성 판단기준에 따라 grade 2(mildly cytotoxic)로 나타난바 생체용으로 적합하다고 볼 수 있다. 본 연구를 통하여 멤브레인형 다공성 지지체 제조에 건조조건이 3차원 다공망의 형성 및 거대기공과 미세기공이 함께 형성되는 것에도 영향을 미치는 것으로 나타났으며 이 결과는 다공성 멤브레인 지지체의 분해성 조절 및 약물 담지 효과를 개선하기 위한 연구에서 다공도의 조절에 대한 기초적인 공정이 될 수 있다.

• Membrane and Water Treatment
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• 제7권2호
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• pp.155-173
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• 2016

The present work has been focused on the development of polysulfone (PSf) ultrafiltration membrane via blending by sulfonated polyethersulfone (SPES) in order to permeability enhancement for ultrafiltration of cheese whey. In this regards, sulfonation of polyethersulfone was carried out and the degree of sulfonation was estimated. The effect of blend ratio on morphology, porosity, permeation and fouling of PSf / SPES membranes was investigated. Filtration experiments of whey were conducted for separation of macromolecules and proteins from the lactose enrichment phase. The morphology and performance of membranes were evaluated using different techniques such SEM, AFM, and contact angle measurements. The contact angle measurement showed that the hydrophilicity of membrane was increased by adding SPES. According to AFM images, PSf / SPES membranes exhibited lower roughness compared to neat PSf membrane. The water and whey flux of these membranes were higher than neat membrane. However, flux was decreased when the PSf / SPES blend ratio was 0/100. It can be attributed to pore size and morphology changes. Further, fouling parameters of PSf membrane were improved after blending. The blend membranes show a great potential to be used practically in proteins separation from cheese whey.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.12.1-12.1
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• 2009

Nano-hydroxyapatite (N-HAp)has shown the pivotal role in producing bone-regenerative materials since it has similarity to natural bone minerals in terms of size, morphology, and the composition. Currently, the combination of biopolymers and N-HAp is recognizedas an attractive approach in generating hybrid scaffolds for bone tissueengineering. Surface engineering is an important issue since it determines whether cells can effectively adhere and proliferate on porous scaffolds. We aim to develop a synthetic approach to porous 3D scaffolds by immobilizing N-HAp on pore surfaces. The discrete nano-level anchoring of N-HAp on the scaffold pore surface is achieved using surface-repellent stable colloidal N-HAp with surface phosphate functionality. This rational surface engineering enables surface-anchored N-HAp to express its overall intrinsic bioactivity,since N-HAp is not phase-mixed with the polymers. The porous polymer scaffolds with surface-immobilized N-HAp provide more favorable environments thanconventional bulk phase-mixed polymer/N-HAp scaffolds in terms of cellular interaction and growth. In vitro biological evaluation using alkalinephosphatase activity assay supports that immobilized N-HAp on pore surfaces of polymer scaffolds contributed to the more enhanced in vitro osteogenicpotential. Besides, the scaffolds with surface-exposed N-HAp provide favorable environments for enhanced in vivo bone tissue growth, estimated by characteristic biomarkers of bone formation such as collagen. The results suggest that newly developed hybrid scaffolds with surface-immobilized N-HApmay serve as a useful 3D substrate with pore surfaces featuring excellent bonetissue-regenerative properties. Acknowledgement. This research was supported by a grant (code #: 2009K000430) from 'Center for Nanostructured Materials Technology' under '21st Century Frontier R&D Programs' of the Ministry of Education, Science and Technology, Korea.

• 분석과학
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• 제22권3호
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• pp.247-253
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• 2009

단결정의 실리콘 웨이퍼를 hydrofluoric acid와 ethyl alcohol이 혼합된 용액에 담궈 적정한 전류를 흘려주면 웨이퍼 표면에 수많은 pore를 형성하면서 에칭되어진다. 이러한 pore의 형태와 porosity는 전류 값과 에칭 시간 및 주기를 변화시켜 쉽게 조절할 수 있는데, 이렇게 제작된 다공성 실리콘은 수백 $m^2/cm^3$의 큰 표면적을 가지게 된다. 이때 sin 파와 같은 모양으로 시간대별 가해지는 전류 밀도를 다르게 해주어 pore안쪽의 모양을 변화시켜 주어 가시광선 영역에서 하나의 spectrum을 나타나게 되는 rugate 박막을 제작 한다. 본 연구에서는 법과학적인 목적으로 코드화된 다공성 실리콘의 rugate film을 이용하여 nano particle을 제작한 다음 이 입자들을 페인트에 혼합, 차량에 도포하고, 회수 후에 이를 확인할 수 있는지 조사하였다. 본 연구에서는 또 다양하게 가해지는 전류 값을 변경 또는 혼합하여 다공성 실리콘에 다양한 코드화를 시도하였으며, 사고 시 탈착한 페인트에서 다공성 실리콘 nano particle을 회수 하기위해 다공성 실리콘 안에 magnetite를 삽입하여 자석을 이용한 미량 나노입자 시료를 응집시켜 스펙트럼을 확인하였다.