• Journal of Pharmaceutical Investigation
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• 제40권4호
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• pp.255-261
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• 2010

Pluronic as pharmaceutical excipients are listed in the US and British Pharmacopoeia. In particular, Pluronics exist as different compositions and display abundant phases as self-assembling into polymeric micelles with various morphologies depending on the aqueous solvent quality, the composition of structure, and hydrophilic-lipophilic balance (HLB). Pluronics were also known as a P-gp modulator, which was exploited as a reversal molecule of multi-drug resistant (MDR) cancers. We selected a lamella forming Pluronic L92 which has high hydrophobicity and relatively long PEO block among L series of Pluronics. The dispersion of L92 showed great size particles and low stability. To increase the stability and to decrease the particle size, secondary Pluronics (F68, F88, F98, F127, P85, P105, and P123) with relatively long PEO chain were added into 0.1 wt% Pluronic L92 dispersion. The stability of binary systems was increased due to incorporated long PEO chain. Their particle sizes slightly decreased to over 200~400 nm and their solubilization capacity of binary systems didn't change except Pluronic L92/P123 mixtures. The L92/P123 systems showed ca. 100 nm sizes and lowest turbidity among the all systems. The solubilization capacity of 0.1 wt% L92/0.1 wt% P123 was slightly increased compared to 0.1 wt% L92 mono system and other binary systems. These nano-sized binary systems may have potential as alternative drug delivery systems with simple preparation method and overcome the drawbacks of mono systems such as low stability and loading capacity.

• 폴리머
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• 제26권6호
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• pp.821-828
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• 2002

미량의 Pluronics가 첨가된 PLLA/l,4-dioxane/water의 삼성분계상을 온도 변화로 유도된상 분리법을 이용하여 10~300 $\mu\textrm{m}$의 공극 크기를 가지며 공극 간의 연결성이 우수한 PLLA 다공성 지지체를 제조하였다. 순수한 PLLA 용액에 Pluronics를 첨가하면 상 분리 온도가 P-123< F-68< F-127 순서로 순차적으로 상승한다. 이는 Pluronics의 양 말단 사슬인 PEO의 영향으로 상분리 진행이 촉진되기 때문이다. 상 분리 온도의 상승으로 스피노달 영역을 증가시켜 높은 온도에서 상 분리 유도가 가능하게 된다. 또한 상 분리 진행 시간 동안에는 계면에 흡수된 Pluronics가 거대 구조를 안정화시켜 상 분리 진행 속도를 지연시키게 된다.

• 한국세라믹학회지
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• 제44권11호
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• pp.650-654
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• 2007

[ $SnO_2$ ]-doped $TiO_2$ thin films were prepared from tin (IV) bis (acetylacetonate) dichloride and titanium diisopropoxide bis (acetylacetonate) with pluronic P123 or degussa P25 as a structural-directing agent. These hydrolyzed sol were spin coated onto Si(100) wafer substrate. The microstructure, morphology and bonding states of thin films were studied by field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of these films was investigated by using indigo carmine solution.

• 한국세라믹학회지
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• 제45권5호
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• pp.297-302
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• 2008

To direct the evolution of nanostructure and immobilize ${\gamma}-Al_2O_3$ catalyst, nanocrystalline La-doped-$Al_2O_3$ powder were prepared by the sol-gel process with addition of an amphiphilic block copolymer template (pluronic P123: $(poly(ethyleneoxide)_{20}-poly(propyleneoxide)_{70}-poly(ethyleneoxide)_{20})$. The dried gel is amorphous, whereas heating at temperature above $700^{\circ}C$ leads to the formation of nanocrystalline ${\gamma}$ and ${\delta}-Al_2O_3$ and these two phases is kept until $1100^{\circ}C$. ${\alpha}-A1_2O_3 $starts to form at $1200^{\circ}C$ with $LaAl_{11}O_{18}$. The surface morphology and crystal structure has been observed by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD). Solid state $^{27}Al$ MAS NMR indicates two types of local environment, i.e. octahedral and tetrahedral sites. The surface area and pore size was compared among these powders using the BET nitrogen adsorption measurements.

• Korean Chemical Engineering Research
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• 제47권3호
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• pp.275-280
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• 2009

바나듐이 담지된 3차원 입방구조의 V-KIT-6를 Pluronic P123 공중합체를 구조형성제로 사용하고, 부탄올을 보조 계면활성제로 사용하여 TEOS와 $NH_4VO_3$로부터 수열합성법으로 제조하였다. 제조한 V-KIT-6는 좁은 기공분포(~6.0 nm)를 가지고 넓은 비표면적(${\sim}1,000m^2/g$)을 보여주었다. V-KIT-6에서 V의 배위 특성 등은 $^{51}V$ 스핀 공명 NMR과 ESR을 이용하여 분석하였다. 제조된 V-KIT-6는 테트라부틸 하이드로 퍼옥사이드(TBHP)를 산화제로 사용한 스티렌의 직접산화반응에서 우수한 촉매활성을 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.1978-1980
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• 2009

A mesostructured form of carbon was fabricated from a template of mesostructured silica by using pentane, an aliphatic hydrocarbon precursor. To synthesize the mesostructured silica, a buffered (pH of 6.5) mixture of nonionic Pluronic P123 surfactant, sodium silicate, and acetic acid were used. The impregnated silica with Fe$(CO)_5$ (wt 5%) and pentane was placed in a quartz tube, treated with pentane vapor at 800 ${^{\circ}C}$ for two hours to synthesize the mesostructured carbon. The XRD patterns of the carbon replica in the low/wide angle regions, its TEM images, and nitrogen adsorption-desorption isotherm revealed that the long-range framework order of mesostructure with the pore size centered on 2.8 nm was maintained to some extent mainly due to some portions of mesophase carbon that work as a support to fix the hexagonal frameworks by anchoring on the pore surface with an improved graphitic character. The dc conductivity of the mesostructured carbon in pressed powder form at 6.0 MPa was 2.08 S/cm.

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1653-1668
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• 2005

Assembly of hybrid mesophases through the combination of amphiphilic block copolymers, acting as structuredirecting agents, and silicon sources using low acid catalyst concentration regimes is a versatile strategy to produce large quantities of high-quality ordered large-pore mesoporous silicas in a very reproducible manner. Controlling structural and textural properties is proven to be straightforward at low HCl concentrations with the adjustment of synthesis gel composition and the option of adding co-structure-directing molecules. In this account, we illustrate how various types of large-pore mesoporous silica can easily be prepared in high phase purity with tailored pore dimensions and tailored level of framework interconnectivity. Silica mesophases with two-dimensional hexagonal (p6mm) and three-dimensional cubi (Fm$\overline{3}$m, Im$\overline{3}$m and Ia$\overline{3}$d) symmetries are generated in aqueous solution by employing HCl concentrations in the range of 0.1−0.5 M and polyalkylene oxide-based triblock copolymers such as Pluronic P123 $(EO_{20}-PO_{70}-EO_{20})$ and Pluronic F127 $(EO_{106}-PO_{70}-EO_{106})$. Characterizations by powder X-ray diffraction, nitrogen physisorption, and transmission electron microscopy show that the mesoporous materials all possess high specific surface areas, high pore volumes and readily tunable pore diameters in narrow distribution of sizes ranging from 4 to 12 nm. Furthermore, we discuss our recent advances achieved in order to extend widely the phase domains in which single mesostructures are formed. Emphasis is put on the first synthetic product phase diagrams obtained in $SiO_2$-triblock copolymer-BuOH-$H_2O$ systems, with tuning amounts of butanol and silica source correspondingly. It is expected that the extended phase domains will allow designed synthesis of mesoporous silicas with targeted characteristics, offering vast prospects for future applications.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3570-3576
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• 2013

Poly(methacrylic acid)-functionalized SBA-15 silicas (denoted as P-x-PMA/SBA-15 where x is molar ratio of TSPM/(TEOS+TSPM) in percentage in the initial mixture) were synthesized by co-condensation of tetraethoxysilane and varying contents of 3-(trimethoxysilyl)propyl methacrylate in acidic medium with the block copolymer Pluronic 123 as a structure directing agent and then polymerization by methacrylic acid in the presence of ammonium persulfate as an initiator. The functionalized materials were characterized by PXRD, TEM, SEM, IR, and $N_2$ adsorption-desorption at 77 K. The investigation of phenol adsorption in aqueous solution on the materials showed that the poly(methacrylic acid)-functionalized mesoporous silicas possess strong adsorption ability for phenol with interaction of various kinds of hydrogen bonds. The adsorption data were fitted to Langmuir isotherms and the maximum adsorption capacity of the three functionalized materials P-5-PMA/SBA-15, P-10-PMA/SBA-15, and P-15-PMA/SBA-15 to be 129.37 mg/g, 187.97 mg/g, and 78.43 mg/g, respectively, were obtained. The effect of the pH on phenol adsorption was studied.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2333-2337
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• 2007

Nanoporous TiO2 and ZrO2 thin films were spin-coated using a surfactant-templated approach from Pluronic P123 (EO20PO70EO20) as the templating agent, titanium alkoxide (Ti(OC4H9)4) as the inorganic precursor, and butanol as a the solvent. The control of the electronic structure of TiO2 is crucial for its various applications. We found that the band gap of the hybrid nanoporous thin films can be easily tuned by adding an acetylacetonestabilized Zr(OC4H9)4 precursor to the precursor solution of Ti(OC4H9)4. Pores with a diameter of 5 nm-10 nm were randomly dispersed and partially connected to each other inside the films. TiO2 and ZrO2 thin films have an anatase structure and tetragonal structure, respectively, while the TiO2-ZrO2 hybrid film exhibited no crystallinity. The refractive index was significantly changed by varying the atomic ratio of titanium to zirconium. The band gap for the nanoporous TiO2 was estimated to 3.43 eV and that for the TiO2-ZrO2 hybrid film was 3.61 eV.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1118-1120
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• 2009

Micro-size CdS spheres of hollow shape were fabricated through the self-assembly of high density arrow-like nanorods. The synthesis of the CdS hollow spheres were accomplished in an aqueous solution of cadmium nitrate and triblock copolymer (Pluronic P123) at low temperature (80 ${^{\circ}C}$) through the slow release of S2- ions from thioacetamide. Morphology of the fabricated CdS hollow spheres was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results indicate that the arrow-like CdS nanorods are simultaneously grown and attached each other to form the building units that become the spheres with hollow inside as a self-assembled process. The CdS spheres have a diameter of $2{\sim}3 {\mu}m$ and consist of the nanorods with a length of$\sim$800 nm. The nanocrystal building blocks have a hexagonal CdS structure.