• Applied Chemistry for Engineering
• /
• v.9 no.2
• /
• pp.273-277
• /
• 1998

The synthesis of hydroxy-terminated poly(propylene carbonate)(HTPPC) was performed by the reaction of propylene carbonate(PC) with alcohol initiator using metal alkoxides, crown ethers and quaternary onium salts as catalysts. The effects of catalyst structure, types and concentration of alcohol, and solvent were investigated. Among the alkoxide catalysts tested, the ones with higher Lewis acidity and with more nucleophilic alkoxide anion showed higher catalytic activity. Mixed catalysts of metal alkoxied and crown ether showed higher conversion of PC than metal alkoxide alone. Quaternary onium salts of bulky cation exhibited higher catalytic activity. High polar solvent showed higher yield of HTPPC and the yield increased with the decrease of [PC]/[Initiator] ratio.

• Polymer(Korea)
• /
• v.36 no.5
• /
• pp.599-605
• /
• 2012

The physicochemical properties such as surface hardness, solvent mechanical wear resistance, and resistance to scratch properties of poly(3,4-ethylenedioxythiophene) (PEDOT) thin film prepared by vapor phase polymerization (VPP) was effectively improved by post-treatment of various metal alkoxide sol solutions. Metal oxide layer derived from sol-gel process of metal alkoxide was generated on the PEDOT thin film layer by VPP, resulting in improving mechanical properties of the conductive thin films without any deterioration of their original surface resistance. Several kinds of silicone and titanium alkoxide derivatives with various functional groups were used as metal alkoxide sol sources. Among them, PEDOT-metal oxide composite thin film derived tetraethyl orthosilicate showed the best performance in the terms of surface resistance, transmittance, and various physicochemical properties. The effect of metal alkoxide content in washing solution, oxidant content and drying temperature have been investigated in order to optimize the various properties of PEDOT-metal oxide composite thin film.

• Journal of the Korean Ceramic Society
• /
• v.30 no.12
• /
• pp.987-992
• /
• 1993

In order to synthesize the heat resistance ceramics of LAS system, we studied on preparing the fine powder with homogeneity by sol-gel method using metal alkoxide. Various results were obtained depending on the composition and process. When the amount of H2O added at initial stage is higher than 10mol/$\ell$, and when the amount of catalyst is 0.1mol/$\ell$, the particle size of synthesized hydrate becomes finer. On condition that partial prehydrolysis time of TEOS is more than 50 hours, the monosized fine powder is obtained(below 1${\mu}{\textrm}{m}$).

• Journal of the Korean Ceramic Society
• /
• v.21 no.2
• /
• pp.127-134
• /
• 1984

Basic research on the formation of monolithic glasses from metal alkoxide has been done concerning gelling of silicon alkoxides and dehydration of those gells. The felling time were increased with increasing of Carbon number of alkyl radical of alkoxide and am-ount of water and the lower pH value of water. Large portions of water and organic materials were rem-oved below 25$0^{\circ}C$ and shrinkage of glass took place above 80$0^{\circ}C$ Therefore heating up to 25$0^{\circ}C$ and above 75$0^{\circ}C$ must be done gradually with rate of 0.5$^{\circ}C$/min.

• Journal of the Korean Ceramic Society
• /
• v.32 no.1
• /
• pp.45-50
• /
• 1995

In order to densify LAS(Lithuim Aluminosilicate)system compounds, we used metal alkoxides as precursors. Also Mg was added by sol-gel method using metal alkoxides to the LAS system for improving the sinterability, thermal and mechanical properties. The result was that the synthesizing temperature was lowered about 10$0^{\circ}C$, the sintering temperature was lowered by over 10$0^{\circ}C$ and MOR of samples from metal alkoxides was two times larger than that of sample form oxide.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.5 no.4
• /
• pp.332-342
• /
• 1995

The important factors of reaction conditions in sol-gel transition of silicon alkoxide solution have been reviewed and discussed on the basis of Raman study. Various factors such as type of catalyst, alkoxide, solvent, drying control chemical additive and water content affect the conversion mechanism in sol-gel process.

• Journal of the Korean Ceramic Society
• /
• v.32 no.11
• /
• pp.1233-1240
• /
• 1995

LAS system, which is difficult to be sintered, was densified by using the powder synthesized from metal alkoxides. Sinterability, thermal and mechanical properties were improved through synthesizing the complex oxide powder from the addition of Ge as an alkoxide. As a result, the synthesizing and sintering temperature of the LAS system lowered by about 10$0^{\circ}C$ and its modulus of rupture (MOR) increased twice higher compared to the sample from the oxide by the direct method.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.76.2-76.2
• /
• 2013

Advanced electronic application areas have strongly required new materials due to the continuous shrinking dimensions of their devices. Specially, the development and use of metal precursors for atomic layer deposition has been extensively focused on application to electronic devices. Thus the systematic design and synthesis of metal compounds with relevant chemical and physical properties, such as stability, volatility, and resistance to air and moisture are very important in the vacuum deposition fields. In many case, organic ligands for metal precursors are especially focused in the related research areas because the large scale synthesis of the metal complexes with excellent properties exclusively depends on the potential usefulness of the ligands. It is recommended for metal complexes to be in monomeric forms because mononuclear complexes generally show high vapor pressures comparing with their oligomeric structure such as dimer and trimer. Simple metal alkoxides complexes are involatile except several examples such as Ti(OiPr)4, Si(OEt)4, and Hf(OtBu)4. Thus the coordinated atom of alkoxide ligands should be crowded in its own environment with some substituents by prohibiting the coordinated atoms from bonding to another metal through oxygen-bridging configuration. Alkoxide ligands containing donor-functionalized group such as amino and alkoxy which can induce the increasing of the coordinative saturation of the metal complexes and the decreasing of the intermolecular interaction between or among the metal compounds. In this presentation, we will discuss the development of metal compounds which adopted donor-functionalized alkoxide ligands derived from their alcohols for electronic application. Some recent results on ALD using metal precursors such as tin, nickel, ruthenium, and tungsten developed in our group will be disclosed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2004.05b
• /
• pp.687-690
• /
• 2004

The preparation of A1203-SiO2 thin films from less than one micron to several tens of microns in thickness had been Prepared from metal alkoxide sols. Two methods, dip-withdrawal and electrophoretic deposition, were employed for thin films and sheets formation. The requirements to be satisfied by the solution for preparing uniform and strong films and by the factors affecting thickness and other properties of the films were examined. For the preparation of thin, continuous A12O3-SiO2 films, therefore, metal-organic-derived precursor solutions contained Si and Al in a chemically polymerized form has been developed and produced in a clear liquid state.

• Journal of the Korean Ceramic Society
• /
• v.31 no.5
• /
• pp.499-504
• /
• 1994

PbTiO3 thin films were prepared by sol-gel spin coating method using metal alkoxide and diethanolamine (DEA). The precipitation of the PbTiO3 sol occurred at pH 7.3 with HNO3 addition, regardless of the amount of DEA. The gelation time of the PbTiO3 sol was reduced with increasing amount of HNO3 and/or water. When the PbTiO3 films prepared by 0.2 molar coating solution were annealed at $650^{\circ}C$ for 30 min, dense and single phase perovskite films were obtained. Dielectric constant and loss tangent of the film were 239 and 0.01 at 1 kHz, respectively.