Reentrant volume phase transition of cross-linked poly(N-isopropylacrylamide) gels in mixed solvents of water/methanol

Soft Matter ◽  
2012 ◽  
Vol 8 (10) ◽  
pp. 3010 ◽  
Author(s):  
Hiroyuki Kojima ◽  
Fumihiko Tanaka
Keyword(s):  
Phase Transition ◽  
Mixed Solvents ◽  
Volume Phase Transition ◽  
Volume Phase

Triply-responsive OEG-based microgels and hydrogels: Regulation of swelling ratio, volume phase transition temperatures and mechanical properties

2021 ◽  
Author(s):  
Dongdong Lu ◽  
Mingning Zhu ◽  
Jing Jin ◽  
Brian R. Saunders
Keyword(s):  
Phase Transition ◽  
Biomedical Engineering ◽  
Volume Phase Transition ◽  
Swelling Ratio ◽  
Transition Temperatures ◽  
Ph Responsive ◽  
Network Systems ◽  
Volume Phase ◽  
Phase Transition Temperatures ◽  
Volume Swelling

Thermally- and pH-responsive microgels (MGs) and hydrogels are fascinating network systems that have been applied in biomedical engineering and sensing. The volume-swelling ratio (Q) and the volume-phase transition temperatures (VPTTs)...

scholarly journals Accounting for Cooperativity in the Thermotropic Volume Phase Transition of Smart Microgels

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 42
Author(s):  
Simon Friesen ◽  
Yvonne Hannappel ◽  
Sergej Kakorin ◽  
Thomas Hellweg
Keyword(s):  
Phase Transition ◽  
Interaction Parameter ◽  
Quantitative Description ◽  
Water Molecules ◽  
Volume Phase Transition ◽  
Network Chain ◽  
Solvent Interaction ◽  
Volume Phase ◽  
The Cross ◽  
Interaction Parameter Χ

A full quantitative description of the swelling of smart microgels is still problematic in many cases. The original approach of Flory and Huggins for the monomer–solvent interaction parameter χ cannot be applied to some microgels. The reason for this obviously is that the cross-linking enhances the cooperativity of the volume phase transitions, since all meshes of the network are mechanically coupled. This was ignored in previous approaches, arguing with distinct transition temperatures for different meshes to describe the continuous character of the transition of microgels. Here, we adjust the swelling curves of a series of smart microgels using the Flory–Rehner description, where the polymer–solvent interaction parameter χ is modeled by a Hill-like equation for a cooperative thermotropic transition. This leads to a very good description of all measured microgel swelling curves and yields the physically meaningful Hill parameter ν. A linear decrease of ν is found with increasing concentration of the cross-linker N,N′-methylenebisacrylamide in the microgel particles p(NIPAM), p(NNPAM), and p(NIPMAM). The linearity suggests that the Hill parameter ν corresponds to the number of water molecules per network chain that cooperatively leave the chain at the volume phase transition. Driven by entropy, ν water molecules of the solvate become cooperatively “free” and leave the polymer network.

Influence of volume phase transition phenomena on the behavior of hydrogel-based valves

2004 ◽  
Vol 99 (2-3) ◽  
pp. 451-458 ◽  
Author(s):  
Andreas Richter ◽  
Steffen Howitz ◽  
Dirk Kuckling ◽  
Karl-Friedrich Arndt
Keyword(s):  
Phase Transition ◽  
Volume Phase Transition ◽  
Volume Phase

Kinetics of the temperature-induced volume phase transition in poly(2-(2-methoxyethoxy)ethyl methacrylate) hydrogels of various topologies

Polymer ◽  
2017 ◽  
Vol 110 ◽  
pp. 25-35 ◽  
Author(s):  
Marcin Pastorczak ◽  
Lidia Okrasa ◽  
Jeong Ae Yoon ◽  
Tomasz Kowalewski ◽  
Krzysztof Matyjaszewski
Keyword(s):  
Phase Transition ◽  
Volume Phase Transition ◽  
Volume Phase ◽  
Ethyl Methacrylate ◽  
Kinetics Of

scholarly journals Re-entrant volume phase transition of hydrogel membrane of microcapsule

2004 ◽  
Vol 38 (3-4) ◽  
pp. 221-225 ◽  
Author(s):  
Takao Yamamoto ◽  
Toshiaki Dobashi ◽  
Daisuke Suzuki ◽  
Takayuki Narita
Keyword(s):  
Phase Transition ◽  
Volume Phase Transition ◽  
Volume Phase ◽  
Hydrogel Membrane
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