Exploration of the unusual two-step volume phase transition of the poly(N-vinylcaprolactam-co-hydroxyethyl methacrylate) hydrogel

2018 ◽  
Vol 20 (35) ◽  
pp. 23013-23024 ◽  
Author(s):  
Gehong Su ◽  
Liyang Jia ◽  
Xueqian Zhang ◽  
Yulin Zhang ◽  
Pengchi Deng ◽  
...  
Keyword(s):  
Phase Transition ◽  
Biomedical Applications ◽  
Volume Phase Transition ◽  
Hydroxyethyl Methacrylate ◽  
Volume Phase ◽  
Transition Mechanism ◽  
Stimuli Sensitive

It is important to investigate the phase transition mechanism of stimuli-sensitive hydrogels due to its great guiding significance for the application of stimuli-sensitive hydrogels in biomedical applications.

Micro-dynamics mechanism of the phase transition behavior of poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) hydrogels revealed by two-dimensional correlation spectroscopy

2017 ◽  
Vol 8 (5) ◽  
pp. 865-878 ◽  
Author(s):  
Gehong Su ◽  
Tao Zhou ◽  
Xifei Liu ◽  
Yanan Ma
Keyword(s):  
Phase Transition ◽  
Ftir Spectroscopy ◽  
Correlation Spectroscopy ◽  
Volume Phase Transition ◽  
Hydroxyethyl Methacrylate ◽  
Two Dimensional ◽  
Phase Transition Behavior ◽  
Temperature Dependent ◽  
Volume Phase ◽  
Transition Behavior

The micro-dynamics mechanism of the volume phase transition of PNIPAM-co-HEMA hydrogels was established using temperature-dependent FTIR spectroscopy, PCMW2D, and 2DCOS analysis.

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.

Two-step volume phase transition mechanism of poly(N-vinylcaprolactam) hydrogel online-tracked by two-dimensional correlation spectroscopy

2017 ◽  
Vol 19 (40) ◽  
pp. 27221-27232 ◽  
Author(s):  
Gehong Su ◽  
Tao Zhou ◽  
Xifei Liu ◽  
Yulin Zhang
Keyword(s):  
Phase Transition ◽  
Ftir Spectroscopy ◽  
Correlation Spectroscopy ◽  
Volume Phase Transition ◽  
Two Dimensional ◽  
Volume Phase ◽  
Transition Mechanism ◽  
Step Mechanism

The volume phase transition of PVCL hydrogel was online-tracked by 2D correlation FTIR spectroscopy, and a two-step mechanism was proposed.

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
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