Dielectric behavior during sol-gel transition of PEO-PPO-PEO triblock copolymer aqueous solution

Song, M.J.; Lee, D.S.; Ahn, JH; Kim, D.J.; Kim, Sung Chul

doi:10.1007/s002890050007

Cited by 46 publications

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“…Researchers have attributed the gelation of Pluronic to the dehydration of PPO groups in the micelle core, a change in the micellar volume, or a decrease in the critical micelle concentration and an increase in the aggregation number. [34][35][36] The effect of Aerosil concentration on sol-gel and gel-sol transition is shown in Figure 4. The incorporation of Aerosil shifted the sol-gel transition to a lower temperature but increased the gel-sol transition temperature.…”

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of Pluronic-colloidal silicon dioxide composite particles as liquid crystal precursor

et al. 2006

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The purpose of this study was to produce spray-dried Pluronic-colloidal silicon dioxide (Aerosil) composite particles as a liquid crystal precursor that would form a liquid crystalline phase upon hydration. A Pluronic-colloidal silicon dioxide dispersion in isopropyl alcohol was spray-dried to obtain composite particles using different concentrations of Aerosil. Polarizing microscopy, gelation, gel melting, and rheological studies were employed to characterize the composite particles. The composite particles obtained were irregular, with concave depression. Gelation was found to decrease with the addition of Aerosil, while gel melting was found to increase with the concentration of Aerosil. Rheological studies showed an increase in elasticity as well as viscosity with an increase in the concentration of Aerosil. Composite particles showed improved gelation and rheological properties. These composite particles and the process by which they were obtained may be useful for designing various drug delivery systems.

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Section: Resultsmentioning

confidence: 99%

Preparation and characterization of Pluronic-colloidal silicon dioxide composite particles as liquid crystal precursor

et al. 2006

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“…Physically, gel formation is related to micellar packing and volume fraction. Researchers have attributed gelation to the dehydration of PPO groups in the micelle core, 32 a change in the micellar volume, 33 or a decrease in the critical micelle concentration and an increase in the aggregation number. 34 The finding that tetracycline lowered the gelation temperature was similar to the result reported by Esposito et al 35 This feature was tentatively explained by a facilitation of the interaction between the hydrophobic portion of the polymer molecules, which could disrupt the micellar structure and increase the entanglement of micelles.…”

Section: Resultsmentioning

confidence: 99%

Development of tetracycline-serratiopeptidase-containing periodontal gel: Formulation and preliminary clinical study

et al. 2006

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The purpose of this research was to reduce the polymer concentration and to obtain reasonable viscosity at a lower concentration of pluronic by the addition of a viscosity modifier. A 20% wt/wt pluronic gel was prepared on a weight basis using the cold method. The effect of the amount of tetracycline and Aerosil on gel properties was studied. The gel was evaluated using different parameters: polarizing microscopy, gelation, gel melting, bioadhesivity, viscosity, drug release, and stability of enzyme. An in vivo study was performed to evaluate the clinical efficiency of the liquid crystalline gel. Addition of Aerosil to the gel favored hexagonal phase formation. Viscosity and bioadhesivity increased with an increase in the concentration of Aerosil. Release of tetracycline was sustained as the concentration of Aerosil increased. Various clinical parameters confirmed the acceptability and efficiency of this gel system.

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“…This forces the quick dehydration of the system and water is released out of the hydrogel with a large gain in entropy, resulting in shrinkage of the polymeric structure (Kopecek, 2003;Ruel-Gariepy & Leroux 2004). The mostly studied temperature responsive hydrogels are methylcellulose (Stabenfeldt et al 2006), hydroxypropyl methylcellulose (Vinatier et al, 2005), chitosan (Zan et al, 2006), Nisopropylacrylamide (NIPAAm) based copolymers (Lu et al, 2000;Kim et al, 2002;Schmaljohann, 2005;Lee et al, 2006;Qiao et al, 2006) and other N-alkylacrylamide polymers (Hirokawa & Tanaka, 1984), poly(vinyl methyl ether) (PVME) (Kabra et al, 1992;Arndt, Schmidt et al 2001;Theiss et al 2004), poly(N-vinylisobutyramide) (PNVIBA) (Akashi et al, 1996;Kunugi et al, 1997;, poly(ethylene oxide-bpropylene oxide-b-ethylene oxide) (PEO-PPO-PEO) (Bohorquez et al, 1999;Song, Lee et al, 2000), and poly(ethylene oxide)/(D,L-lactic acid-co-glycolic acid) (PEO-PLLA-PLGA) (Jeong et al, 1997) copolymers. Poly(N-isopropylacrylamide) (PNIPAAm) is the most popular temperature-responsive polymer since it exhibits a sharp phase transition in water at 34.3 o C which is close to physiological temperature .…”

Section: Temperature Responsive Hydrogelsmentioning

confidence: 99%

Hydrogel Biomaterials

Patel¹,

Mequanint²

2011

Biomedical Engineering - Frontiers and Challenges

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Dielectric behavior during sol-gel transition of PEO-PPO-PEO triblock copolymer aqueous solution

Cited by 46 publications

References 0 publications

Preparation and characterization of Pluronic-colloidal silicon dioxide composite particles as liquid crystal precursor

Preparation and characterization of Pluronic-colloidal silicon dioxide composite particles as liquid crystal precursor

Development of tetracycline-serratiopeptidase-containing periodontal gel: Formulation and preliminary clinical study

Hydrogel Biomaterials

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