Sol–gel transition and phase separation in ternary system of gelatin-water–poly(ethylene glycol) oligomer

2014 ◽  
Vol 200 ◽  
pp. 47-51 ◽  
Author(s):  
Yutaro Yamashita ◽  
Miho Yanagisawa ◽  
Masayuki Tokita
2003 ◽  
Vol 788 ◽  
Author(s):  
Yuki Kobayashi ◽  
Kazuki Nakanishi ◽  
Kazuyuki Hirao

ABSTRACTFormation of hierarchical macropores and mesopores in ethylene-bridged polysilsesquioxane sol-gel systems via concurrent sol-gel transition and phase separation induced by the incorporation of supramolecular templats has been investigated. A series of poly(ethylene-glycol)-poly(propyleneglycol)- poly(ethyleneglycol) triblock copolymers, EOPOEOs, have been employed as supramolecular templates, while 1,2-bis(trimethoxysilyl)ethane was used as a polysilsesquioxane source. Successful combination of templated mesopores and well-defined macropores due to phase-separation has been found in the system with EOPOEOs having 70 PO units and respective 20 EO units. Although similar macroporous morphology has been obtained for all the EOPOEOs with EO chain longer or shorter than 20 units, the optimum composition for the co-continuous macropores and that for templated mesopores deviated from each other, resulting in the failure of producing hierarchical macropores and mesopores.


2017 ◽  
Vol 8 (41) ◽  
pp. 6378-6385 ◽  
Author(s):  
Chisa Norioka ◽  
Kazuma Okita ◽  
Miho Mukada ◽  
Akifumi Kawamura ◽  
Takashi Miyata

We designed biotin-conjugated four-armed poly(ethylene glycol) (biotinylated Tetra-PEG) as biomolecularly stimuli-responsive polymers that underwent the phase transition from a sol to a gel state in response to avidin as a target biomolecule.


2018 ◽  
Vol 20 (30) ◽  
pp. 20287-20295 ◽  
Author(s):  
Sean C. O’Neill ◽  
Ankit D. Kanthe ◽  
Jacob A. Weber ◽  
Raymond S. Tu

We examine the dynamics of the sol–gel transition for end-functionalized linear- and 4-arm-peptides bioconjugated to poly-ethylene glycol (PEG) in aqueous environments with increasingly chaotropic (Cl− < Br− < I−) anions.


2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Satoshi Tanimoto ◽  
Naoto Yagi ◽  
Hitoshi Yamaoka

Poly(L-leucine)-block-poly(ethylene glycol)-block-poly(L-leucine) triblock copolymers were synthesized by a ring-opening polymerization ofα-amino acid N-carboxyanhydride with amino-terminated PEG as an initiator. The chloroform solution of these peptide copolymers showed a thermo-sensitive sol-gel transition. The transition temperature varied as a function of the length of peptide segments. Additionally, we used these peptide copolymers to remove an endocrine disruptor such as bisphenol A from its aqueous solution. As a result, it became clear that the peptide copolymer gel used in this study could capture bisphenol A efficiently.


2012 ◽  
Vol 1403 ◽  
Author(s):  
Harshal D. Santan ◽  
Axel T. Neffe ◽  
Stefan Kamlage ◽  
Andreas Lendlein

ABSTRACTStimuli-sensitive materials can change properties upon exposure to an external stimulus. Thermoreversible gelation upon heating is one example for such a stimuli sensitivity. Here, it is of significance to tailor the transition temperature and to achieve large changes of G’ and the viscosity. Grafting of the thermosensitive poly(ethylene glycol-b-propylene glycol-b-ethylene glycol)s (PEPEs) to pectin was performed in order to investigate if tailoring of the sol-gel-transition temperature can be achieved by adjusting the grafting ratio. PEPEs were aminated and grafted to the polysaccharide via EDC coupling as shown by FTIR. The sol-gel transition of the pectin, PEPE, and the grafted system (PGP) was investigated by rheology. The gelation temperature (Tgel) of the system could be adjusted by varying the grafting density of PEPE onto pectin as well as by the concentration of the thermosensitive polymer in aqueous solution. A concentration of 15 – 20 wt% of the grafted system in water led to gelation temperatures in the range of 25 – 33 °C and the critical micelle concentration (CMC) and critical micelle temperature (CMT) of the grafted systems were determined by UV spectroscopy. The viscosity and the G’ increased by four orders of magnitudes at Tgel, which is comparable to PEPEs alone, but could be reached at lower PEPE concentrations. In the future, a thorough mechanistic investigation of the gelation process would be of interest.


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