Spinodal Phase Separation in a Macromolecular Sol → Gel Transition

1974 ◽  
Vol 7 (4) ◽  
pp. 527-530 ◽  
Author(s):  
G. T. Feke ◽  
W. Prins
Keyword(s):  
Phase Separation ◽  
Sol Gel ◽  
Sol Gel Transition ◽  
Gel Transition

Controlled Hierarchical Pore Structures in Ethylene-Bridged Polysilsesquioxane Gels

2003 ◽  
Vol 788 ◽  
Author(s):  
Yuki Kobayashi ◽  
Kazuki Nakanishi ◽  
Kazuyuki Hirao
Keyword(s):  
Phase Separation ◽  
Ethylene Glycol ◽  
Triblock Copolymers ◽  
Sol Gel ◽  
Poly Ethylene Glycol ◽  
Bridged Polysilsesquioxane ◽  
Sol Gel Transition ◽  
Poly Ethylene ◽  
Hierarchical Pore ◽  
Gel Transition

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.

Macroporous Morphology Induced by Phase Separation in Sol-Gel Systems Derived from Titania Colloid

2003 ◽  
Vol 788 ◽  
Author(s):  
Junko Konishi ◽  
Koji Fujita ◽  
Kazuki Nakanishi ◽  
Kazuyuki Hirao
Keyword(s):  
Crystal Structure ◽  
Phase Separation ◽  
Sol Gel ◽  
Domain Size ◽  
Colloidal Dispersion ◽  
Titanium Alkoxide ◽  
Titania Gel ◽  
Sol Gel Transition ◽  
Titania Sol ◽  
Gel Transition

ABSTRACTMacroporous titania gels have been prepared by the sol-gel method starting from aqueous colloidal dispersion of titania. The use of titania sol instead of highly reactive titanium alkoxide allows us to control the rate of gelation. Macroporous morphology is formed when the transitional structure of phase separation is fixed as permanent structures by the sol-gel transition. The domain size can be controlled reproducibly by changing the starting composition. The crystal structure of the titania gel is transformed from anatase to rutile through the heat treatment at 900°C, while the macroporous morphology remains unchanged.

High surface area hierarchical porous Al2O3 prepared by the integration of sol–gel transition and phase separation

RSC Advances ◽  
2016 ◽  
Vol 6 (62) ◽  
pp. 57217-57226 ◽  
Author(s):  
A. R. Passos ◽  
S. H. Pulcinelli ◽  
V. Briois ◽  
C. V. Santilli
Keyword(s):  
Phase Separation ◽  
Surface Area ◽  
Porous Alumina ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Gelation Process ◽  
Hierarchical Porous ◽  
Sol Gel Transition ◽  
Gel Transition

Mechanism of gelation process and phase separation for production of hierarchical porous alumina with high surface area.

Phase Separation in Silica Sol-gel System Containing Anionic Surfactant

2007 ◽  
Vol 1056 ◽  
Author(s):  
Taisuke Matsui ◽  
Kazuki Nakanishi ◽  
Kazuyoshi Kanamori ◽  
Teiichi Hanada
Keyword(s):  
Phase Separation ◽  
Anionic Surfactants ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Solvent Phase ◽  
Heat Treated ◽  
Sol Gel Transition ◽  
Moderate Interaction ◽  
Gel Transition

ABSTRACTBy inducing phase separation parallel to the sol-gel transition of alkoxy-derived silica systems, silica monoliths with well-defined co-continuous macropores were obtained from the systems containing anionic surfactants. We adopted three kinds of anionic surfactants which differ from each other in the length of alkyl chain (CH3(CH2)17SO3Na, CH3(CH2)15SO3Na, CH3(CH2)13SO3Na). Mesopores were also found in the silica skeletons presumably by the supramolecular templating. Characterization of the dried or heat-treated samples was carried out by a scanning electron microscope (SEM) and nitrogen adsorption measurements. Experimental results showed that due to the moderate interaction between silica oligomers and surfactants, most of the surfactants are distributed to the solvent phase which determines the macropore volume. The median size and volume of the macropores could be controlled independently by the starting composition. In the absence of any additive to enhance templating by the surfactant, the samples exhibited only amorphous mesopores.

Sol-gel transition in silica alkaline solutions. A NMR study

1994 ◽  
Vol 91 ◽  
pp. 901-908 ◽  
Author(s):  
H Zanni ◽  
P Nieto ◽  
L Fernandez ◽  
R Couty ◽  
P Barret ◽  
...  
Keyword(s):  
Sol Gel ◽  
Alkaline Solutions ◽  
Nmr Study ◽  
Sol Gel Transition ◽  
Gel Transition

scholarly journals Synthesis of Nanogels: Current Trends and Future Outlook

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 36
Author(s):  
Emanuele Mauri ◽  
Sara Maria Giannitelli ◽  
Marcella Trombetta ◽  
Alberto Rainer
Keyword(s):  
3D Printing ◽  
Ad Hoc ◽  
Sol Gel ◽  
Controlled Polymerization ◽  
Current Trends ◽  
Chip Technology ◽  
Physico Chemical ◽  
Physical Interactions ◽  
Sol Gel Transition ◽  
Gel Transition

Nanogels represent an innovative platform for tunable drug release and targeted therapy in several biomedical applications, ranging from cancer to neurological disorders. The design of these nanocarriers is a pivotal topic investigated by the researchers over the years, with the aim to optimize the procedures and provide advanced nanomaterials. Chemical reactions, physical interactions and the developments of engineered devices are the three main areas explored to overcome the shortcomings of the traditional nanofabrication approaches. This review proposes a focus on the current techniques used in nanogel design, highlighting the upgrades in physico-chemical methodologies, microfluidics and 3D printing. Polymers and biomolecules can be combined to produce ad hoc nanonetworks according to the final curative aims, preserving the criteria of biocompatibility and biodegradability. Controlled polymerization, interfacial reactions, sol-gel transition, manipulation of the fluids at the nanoscale, lab-on-a-chip technology and 3D printing are the leading strategies to lean on in the next future and offer new solutions to the critical healthcare scenarios.

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