Predictions of thermoreversible volume phase transitions in copolymer gels by lattice-fluid-hydrogen-bond theory

1997 ◽  
Vol 106 (11) ◽  
pp. 4768-4772 ◽  
Author(s):  
A. K. Lele ◽  
I. Devotta ◽  
R. A. Mashelkar
Keyword(s):  
Hydrogen Bond ◽  
Phase Transitions ◽  
Volume Phase ◽  
Lattice Fluid ◽  
Copolymer Gels ◽  
Bond Theory

Temperature-Sensitive Nanogels PNIPAAm/DMA Prepared and Research

2012 ◽  
Vol 465 ◽  
pp. 141-145
Author(s):  
Hai Yan Wang ◽  
Qian Liao ◽  
Qiao Lan Shao ◽  
Gao Qiu ◽  
Xi Hua Lu
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Synthesis And Characterization ◽  
Temperature Sensitive ◽  
Volume Phase Transition ◽  
Volume Phase ◽  
New Class ◽  
Copolymer Gels ◽  
Temperature Controlled

There have much study about thermo-responsive nanogels,which exhibit temperature-controlled volume phase transitions.There have been few reports,however,of electrostatically neutral,thermosensitive nanogels with a high composition of hydrophilic monomer.Here,we describe the synthesis and characterization of a new class of nonionic copolymer nanogels based on N-ispropylacrylamide(NIPAM) and N,N-dimethylacrylamide(DMA),wich exhibit tunable volume phase transition temperatures.And increasing percentages of DMA in copolymer gels raises the LCST,and attenuates and broadens the volume phases transition.Through DLS, AFM and UV-Vis measurement it's size,shape and VPTTs.The character of nonionic NIPAM/DMA nanogels show it's tunable phase transitions promise to be useful for applicatipns in biotechnology and medicine.

Potential model for tunnel proton transfer in hydrogen bond theory

1998 ◽  
Vol 41 (5) ◽  
pp. 399-407
Author(s):  
A. S. Vshivtsev ◽  
A. F. Korolev ◽  
K. G. Kruglov ◽  
A. V. Tatarintsev
Keyword(s):  
Hydrogen Bond ◽  
Proton Transfer ◽  
Potential Model ◽  
Bond Theory

scholarly journals Wave onset in central gray matter - its intrinsic optical signal and phase transitions in extracellular polymers

2001 ◽  
Vol 73 (3) ◽  
pp. 351-364 ◽  
Author(s):  
VERA M. FERNANDES-DE-LIMA ◽  
JOÃO E. KOGLER ◽  
JOCELYN BENNATON ◽  
WOLFGANG HANKE
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Gray Matter ◽  
Action Potentials ◽  
Optical Signal ◽  
Excitable Media ◽  
Extracellular Polymers ◽  
Axon Membrane ◽  
Intrinsic Optical Signal ◽  
Volume Phase

The brain is an excitable media in which excitation waves propagate at several scales of time and space. ''One-dimensional'' action potentials (millisecond scale) along the axon membrane, and spreading depression waves (seconds to minutes) at the three dimensions of the gray matter neuropil (complex of interacting membranes) are examples of excitation waves. In the retina, excitation waves have a prominent intrinsic optical signal (IOS). This optical signal is created by light scatter and has different components at the red and blue end of the spectrum. We could observe the wave onset in the retina, and measure the optical changes at the critical transition from quiescence to propagating wave. The results demonstrated the presence of fluctuations preceding propagation and suggested a phase transition. We have interpreted these results based on an extrapolation from Tasaki's experiments with action potentials and volume phase transitions of polymers. Thus, the scatter of red light appeared to be a volume phase transition in the extracellular matrix that was caused by the interactions between the cellular membrane cell coat and the extracellular sugar and protein complexes. If this hypothesis were correct, then forcing extracellular current flow should create a similar signal in another tissue, provided that this tissue was also transparent to light and with a similarly narrow extracellular space. This control tissue exists and it is the crystalline lens. We performed the experiments and confirmed the optical changes. Phase transitions in the extracellular polymers could be an important part of the long-range correlations found during wave propagation in central nervous tissue.

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