scholarly journals Influence of cross-linking density on volume phase transition of liquid crystalline gels in a nematogenic solvent

2003 ◽  
Vol 118 (21) ◽  
pp. 9854-9860 ◽  
Author(s):  
Yuko Okuno ◽  
Kenji Urayama ◽  
Shinzo Kohjiya
Keyword(s):  
Phase Transition ◽  
Liquid Crystalline ◽  
Cross Linking ◽  
Volume Phase Transition ◽  
Volume Phase

Volume phase transition mechanism of poly[oligo(ethylene glycol)methacrylate] based thermo-responsive microgels with poly(ionic liquid) cross-linkers

2015 ◽  
Vol 17 (38) ◽  
pp. 25525-25535 ◽  
Author(s):  
Yuanyuan Zhou ◽  
Hui Tang ◽  
Peiyi Wu
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Fourier Transform ◽  
Ethylene Glycol ◽  
Cross Linking ◽  
Volume Phase Transition ◽  
Glycol Methacrylate ◽  
Volume Phase ◽  
Transition Mechanism ◽  
Poly Ionic Liquid

Thermodynamic volume phase transition mechanisms of poly[oligo(ethylene glycol)methacrylate] (POEGMA) microgels with poly(ionic liquid) (PIL) cross-linking moieties were investigated in detail on the basis of Fourier transform infrared (FTIR) spectroscopy.

Photo-Cross-Linkable PNIPAAm Copolymers. 4. Effects of Copolymerization and Cross-Linking on the Volume-Phase Transition in Constrained Hydrogel Layers

Langmuir ◽  
2003 ◽  
Vol 19 (26) ◽  
pp. 10947-10956 ◽  
Author(s):  
Marianne E. Harmon ◽  
Dirk Kuckling ◽  
Pradeep Pareek ◽  
Curtis W. Frank
Keyword(s):  
Phase Transition ◽  
Cross Linking ◽  
Volume Phase Transition ◽  
Volume Phase

Volume Phase Transition of Liquid Crystalline Gels in a Nematic Solvent

2002 ◽  
Vol 35 (12) ◽  
pp. 4567-4569 ◽  
Author(s):  
Kenji Urayama ◽  
Yuko Okuno ◽  
Takanobu Kawamura ◽  
Shinzo Kohjiya
Keyword(s):  
Phase Transition ◽  
Liquid Crystalline ◽  
Volume Phase Transition ◽  
Volume Phase ◽  
Nematic Solvent

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
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