lH Nmr Studies of the Sol-Gel Transition

1984 ◽  
Vol 32 ◽  
Author(s):  
Roger A. Assink ◽  
Bruce D. Kay
Keyword(s):  
Sol Gel ◽  
Chemical Species ◽  
High Magnetic Fields ◽  
Nmr Studies ◽  
H Nmr ◽  
Acid And Base ◽  
Sol Gel Transition ◽  
Product Species ◽  
Different Time Scales ◽  
Gel Transition

ABSTRACTHigh resolution 1H NMR spectroscopy has been employed to study the dynamics of the sol-gel transition in simple silicates. High magnetic fields (360 MHz) were used to detect and identify the various chemical species present in the Si(OCH2CH3)4:C2H5OH:H2O sol-gel system. Using these techniques, the time evolution of the reactant and product species were monitored. The results of these studies have shown that acid and base catalyzed systems react along very different chemical pathways and that the elementary hydrolysis and condensation reactions occur on widely different time scales.

High field 1H NMR Studies of Sol-Gel Kinetics

1986 ◽  
Vol 73 ◽  
Author(s):  
Bruce D. Kay ◽  
Roger A. Assink
Keyword(s):  
Equilibrium Distribution ◽  
Sol Gel ◽  
Nmr Studies ◽  
H Nmr ◽  
Rate Limiting Step ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Product Species ◽  
Rate Limiting ◽  
Kinetics Of

ABSTRACTHigh resolution 1H NMR spectroscopy at high magnetic fields is employed to study the reaction kinetics of the Si(OCH3)4:CH3OH:H2O sol-gel system. Both the overall extent of reaction as a function of time and the equilibrium distribution of species are measured. In acid catalyzed solution, condensation is the rate limiting step while in base catalyzed solution, hydrolysis becomes rate limiting. A kinetic model in which the rate of hydrolysis is assumed to be independent of the adjacent functional groups is presented. This model correctly predicts the distribution of product species during the initial stages of the sol-gel reaction.

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.

Analyzing the Effects of Silica Nanospheres on the Sol–Gel Transition Profile of Thermosensitive Hydrogels

Langmuir ◽  
2021 ◽  
Author(s):  
Lucas S. Ribeiro ◽  
Renata L. Sala ◽  
Leticia A. O. de Jesus ◽  
Sandra A. Cruz ◽  
Emerson R. Camargo
Keyword(s):  
Sol Gel ◽  
Silica Nanospheres ◽  
Thermosensitive Hydrogels ◽  
Sol Gel Transition ◽  
Gel Transition ◽  
Transition Profile
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