• Bulletin of the Korean Chemical Society
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• 제27권6호
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• pp.808-816
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• 2006

Among the many forms of mesoporous materials, thin films are important for the potential applications of this class of materials. Compared with the powder forms, however, there has been relatively little work done on thin films probably because of the lack of suitable and generalized synthetic mechanisms established. In this account, we will review the issues on mesoporous thin films with emphasis on the necessity of forming films with accessible pores from the film surfaces and on mesoporous thin films with metal oxides other than silica. Various methods that have been tried to utilize mesoporous thin films with accessible pores as templates for the synthesis of nanostructured materials are reviewed with the emphasis on the advantages of the electrochemical deposition technique.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2271-2275
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• 2013

We report on the photoelectrochemical properties of partially reduced mesoporous titania thin films. The fabrication is achieved by synthesizing mesoporous titania thin films through the self-assembly of a titania precursor and a block copolymer, followed by aging and calcination, and heat-treatment under a $H_2$ (1 torr) environment. Depending on the temperature used for the reaction with $H_2$, the degree of the reduction (generation of oxygen vacancies) of the titania is controlled. The oxygen vacancies induce visible light absorption, and decrease of resistance while the mesoporosity is practically unaltered. The photoelectrochemical activity data on these films, by measuring their photocurrent-potential behavior in 1 M NaOH electrolyte under AM 1.5G 100 mW $cm^{-2}$ illumination, show that the three effects of the oxygen vacancies contribute to the enhancement of the photoelectrochemical properties of the mesoporous titania thin films. The results show that these oxygen deficient $TiO_2$ mesoporous thin films hold great promise for a solar hydrogen generation. Suggestions for the materials design for improved photoelectrochemical properties are made.

• Tribology and Lubricants
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• 제23권6호
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• pp.298-300
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• 2007

Frictional characteristics of mesoporous $SiO_2$ thin films were evaluated with different pore sizes. The films were manufactured by sol-gel and self-assembly methods to have a porous structure. The pores on the surface may play as the outlet of wear particle and the storage of lubricant so that the surface interactions could be improved. The pores were exposed on the surface by chemical mechanical polishing (CMP) or plasma-etching after forming the porous films. The ball-on-disk tests with mesoporous $SiO_2$ thin films on glass specimen were conducted at sliding speed of 15 rpm and a load of 0.26 N. The results show considerable dependency of friction on pore size of mesoporous $SiO_2$ thin films. The friction coefficient decreased as increasing the pore size. CMP process was very useful to expose the pores on the surface.

• Macromolecular Research
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• 제17권9호
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• pp.697-702
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• 2009

Mesoporous ethanesilica thin film was prepared using PEO-PLGA-PEO triblock copolymers as structure-directing agents and (1,2-bis(triethoxysilyl) ethane BTESE; bridged organosilicates) as inorganic precursors via one-step sol-gel condensation of ethanesilica precursors. The mesostructure of ethanesilica films is critically dependent on the processing experimental parameters after the hydrolyzed silica sol mixture was spin-cast. This study examined the effects of the block copolymer template/organosilica precursor ratio in the casting solution and aging period before calcination of the mesostructure. It was further demonstrated that mesoscopic ordering of organosilicate thin films is induced by the rearrangement of block copolymer template/organosilica hybrid during thermal decomposition of the PEO-PLGA-PEO triblock copolymer. The mesoporous structure and morphology were characterized by SAXS, TEM and solid-state NMR measurement.

• 통합자연과학논문집
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• 제3권4호
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• pp.219-225
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• 2010

On the surface of mesoporous silica thin films (MSTF) which were fabricated by sol-gel approach there are existences of water and three different silanol types including chained, germinal and isolated silanol. Their amounts changes as a function of aging time of used sol solution, as confirmed by FT-IR. The adsorbed water generates ionic carriers such as H+ and OH- and passivates the Si dangling bonds at the interface of silicon wafer-MSTF. The ionic carriers can not only transport across the thickness of thin film to enhance the leakage current but also diffuse toward the silicon wafer-MSTF interface to depassivate Si dangling bonds. On the other hand, chained silanols or germinal silanols promote the moisture adsorption of MSTF and tend to form strongly hydrogen bonded systems with adsorbed water molecules resulting in very high dielectric constant. Isolated silanol, on the contrary, affects less on electrical properties of thin film.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1025-1026
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• 2005

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.282-282
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• 2013

The antimony sulfide ($Sb_2S_3$) thin films were deposited using the gas phase method which known as atomic layer deposition (ALD) on mesoporous micro-films. Tris (dimethylamido) antimony (III[$(Me_2N)_3Sb$] and hydrogensulfide ($H_2S$) were used as precursors to deposit $Sb_2S_3$. Self-terminating nature of $(Me_2N)_3Sb$ and $H_2S$ reaction were demonstrated by growth rate saturation versus precursors dosing time. Absorption spectra and extinction coefficient were investigated by UV-VIS spectroscopy. Scanning electron microscopic analysis and X-ray photoelectron spectroscopy (XPS) depth profile were employed to determine the conformal deposition.

• 한국세라믹학회지
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• 제45권10호
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• pp.631-637
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• 2008

Self-standing mesoporous bioactive glass/poly($\varepsilon$-caprolactone) composite thin films with good molding capability, bioactivity, and biocompatibility in vitro, which may find potential applications in tissue engineering and drug storage, were prepared using a combination of the sol-gel, polymer templating, and water casting method. The thickness of self-standing films was affected by the difference of dielectric constant between distilled water and organic solvent.

• Korean Chemical Engineering Research
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• 제46권4호
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• pp.777-782
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• 2008

초음파 중합법을 이용하여 pyrrole을 중합시킴으로써 polypyrrole 나노입자를 합유하는 메조포러스 $TiO_2$ 박막을 합성하였다. 메조포러스 $TiO_2$ 박막을 만들기 위한 $TiCl_4$-계면활성제 용액에 pyrrole을 넣어주고 초음파 중합시킴으로써 용액 내에 polypyrrole 나노입자들이 잘 분산된 형태로 만들어졌다. 이 용액을 이용하여 spin-coating과 열처리를 함으로써 polypyrrole 나노입자를 합유하는 메조포러스 $TiO_2$ 박막을 제조하였다. 열처리 후에도 기공 구조는 잘 유지되었으며, polypyrrole 나노입자들이 박막 내에 잘 분산되었다. 주형물질인 계면활성제의 종류와 pyrrole의 양을 조절함으로써, 합성된 박막의 기공 크기와 빛의 흡광도를 조절하였다.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3730-3734
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• 2010

A simple, inexpensive and less time consuming electrochemical methods were carried out to prepare ordered mesoporous cobalt films. Ordered mesoporous cobalt films were successfully synthesized by templated electrodepostion of hexagonal $H_1$-e Co ion. The electrodeposited mesopores films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), low angle X-ray diffraction (XRD) and voltammetric methods. The applicability of thin films as high - performance super capacitors electrode materials is demonstrated electrochemically using cyclic voltammetry (CV) technique.