A model for equilibrium swelling of the UCST ‐type thermo‐responsive hydrogels

2021 ◽  
Author(s):  
A.D. Drozdov ◽  
J. deClaville Christiansen
Keyword(s):  
Equilibrium Swelling ◽  
Responsive Hydrogels

Equilibrium swelling and kinetics of pH-responsive hydrogels: models, experiments, and simulations

2002 ◽  
Vol 11 (5) ◽  
pp. 544-555 ◽  
Author(s):  
S.K. De ◽  
N.R. Aluru ◽  
B. Johnson ◽  
W.C. Crone ◽  
D.J. Beebe ◽  
...  
Keyword(s):  
Ph Responsive ◽  
Equilibrium Swelling ◽  
Responsive Hydrogels ◽  
Kinetics Of

scholarly journals Stimuli Responsive Hydrogels: NIPAM/AAm/Carboxylic Acid Polymers

2019 ◽  
Vol 27 (2) ◽  
pp. 155-184 ◽  
Author(s):  
Yasemin Işikver ◽  
Dursun Saraydin
Keyword(s):  
Thermal Analyses ◽  
The Body ◽  
Polymerization Reaction ◽  
Solution Temperature ◽  
Stimuli Responsive ◽  
Scanning Calorimetry ◽  
Equilibrium Swelling ◽  
Different Temperatures ◽  
Swelling Studies ◽  
Responsive Hydrogels

Abstract Stimuli-responsive hydrogels (SRH) were prepared by using monomers (i.e. N-isopropyl acrylamide; NIPAM and acrylamide; AAm), co-monomers (i.e. methacrylic acid; MPA or mesaconic acid; MFA) and a crosslinker (N, N’-methylene bisacrylamide; N-Bis). SRH have been prepared by thermal free radical polymerization reaction in aqueous solution. Spectroscopic and thermal analyses such as Fourier Transform Infrared Spectroscopy, thermogravimetric analysis and differential scanning calorimetry analysis were performed for SRH characterization. The equilibrium swelling studies by gravimetrically were carried out in different solvents, at the solutions, temperature, pH, and ionic strengths to determine their effect on swelling characteristic of the hydrogels. In addition, cycles equilibrium swelling studies were made with the solutions at different temperatures and at different pH. NIPAM/AAm hydrogel exhibits a lover critical solution temperature (LCST) at 28 oC, whereas NIPAM/AAm-MPA and NIPAM/AAm-MFA hydrogels exhibit a LCST at 31 C and 35 oC, respectively, and the LCST of NIPAM/AAm-MFA hydrogel is close to the body temperature.

Using dioxane and water as mixed solvents to prepare pH and temperature dual responsive poly(N-isopropyl acrylamide-co-itaconic acid) hydrogels

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Youdao Ling ◽  
Mangeng Lu
Keyword(s):  
Itaconic Acid ◽  
Mixed Solvents ◽  
Chemical Compositions ◽  
Temperature Responsive ◽  
Dual Responsive ◽  
Isopropyl Acrylamide ◽  
Equilibrium Swelling ◽  
Chain Conformations ◽  
Responsive Hydrogels ◽  
Equilibrium Swelling Ratios

AbstractpH and temperature dual responsive hydrogels based on itaconic acid (IA) and N-isopropylacrylamide (NIPAAm) were prepared by means of water and dioxane as mixed solvents. The chemical compositions, structures and morphologies of these hydrogels were characterized by FTIR, TGA and SEM, and their pH and temperature responsive behaviours were investigated through equilibrium swelling ratios, deswelling and reswelling kinetics. The results showed the hydrogels fabricated in this condition had expanded chain conformations and macroporous network structures, and exhibited the larger swelling ratios as well as improved deswelling/reswelling dynamics.

Mathematical Modeling of Hydrogels for Microfluidic Flow Control

2009 ◽  
Vol 74 ◽  
pp. 33-36 ◽  
Author(s):  
Jundika Candra Kurnia ◽  
Erik Birgersson ◽  
Arun Sadashiv Mujumdar ◽  
Lee Ching Quah
Keyword(s):  
Mathematical Modeling ◽  
Power Supply ◽  
Stimuli Responsive ◽  
Ph Responsive ◽  
Microfluidic Flow ◽  
Equilibrium Swelling ◽  
Conservation Of Momentum ◽  
External Power ◽  
Responsive Hydrogels ◽  
Good Agreement

A mathematical model of a microfluidic controller comprising a hydrogel in a typical T- and Y-junction is derived and presented. The model takes into account conservation of momentum, mass and ions for laminar incompressible flow and the deformation/sensing of a pH-sensitive hydrogel. The response of the pH-responsive hydrogel is validated with experimental equilibrium swelling curves for which good agreement is found. The model is employed to study the behavior of the hydrogel and its impact on the overall fluid flow in different microfluidic flow channel/hydrogel configurations, e.g. in a T-junction, where the hydrogel can act autonomously and without external power supply to regulate the flow. Finally, we discuss how the model can be generalized for other types of stimuli-responsive hydrogels.

In Situ Crosslinking Temperature-Responsive Hydrogels with Improved Delivery, Swelling, and Elasticity for Endovascular Embolization

2019 ◽  
Author(s):  
Derek J. Overstreet ◽  
Amrita Pal ◽  
Brent L. Vernon ◽  
Elizabeth J. Lee
Keyword(s):  
Endovascular Embolization ◽  
Temperature Responsive ◽  
Responsive Hydrogels ◽  
In Situ Crosslinking

Sticky ends in a self-assembling ABA triblock copolymer: the role of ureas in stimuli-responsive hydrogels

2019 ◽  
Vol 4 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Ryan T. Shafranek ◽  
Joel D. Leger ◽  
Song Zhang ◽  
Munira Khalil ◽  
Xiaodan Gu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Viscoelastic Properties ◽  
Triblock Copolymer ◽  
Thermal Response ◽  
Stimuli Responsive ◽  
Self Assembling ◽  
Polymeric Hydrogels ◽  
Aba Triblock Copolymer ◽  
Responsive Hydrogels

Directed self-assembly in polymeric hydrogels allows tunability of thermal response and viscoelastic properties.

Dual pH and temperature responsive hydrogels based on β-cyclodextrin derivatives for atorvastatin delivery

2016 ◽  
Vol 136 ◽  
pp. 300-306 ◽  
Author(s):  
Kaiwen Yang ◽  
Sicheng Wan ◽  
Binbin Chen ◽  
Wenxia Gao ◽  
Jiuxi Chen ◽  
...  
Keyword(s):  
Cyclodextrin Derivatives ◽  
Temperature Responsive ◽  
Responsive Hydrogels

Effect and Detection of Loose Chain Ends in Crosslinked Polyurethane Elastomers

1971 ◽  
Vol 44 (1) ◽  
pp. 152-165 ◽  
Author(s):  
A. E. Oberth
Keyword(s):  
Crosslink Density ◽  
Volume Fraction ◽  
Present Theory ◽  
Swelling Ratio ◽  
Polyurethane Elastomers ◽  
Equilibrium Volume ◽  
Equilibrium Swelling ◽  
Volume Swelling

Abstract The effect of loose chain ends on tensile properties and equilibrium swelling of crosslinked polyurethane rubbers is studied. As in plasticized elastomers, tensile strength and elastic modulus are reduced approximately by a factor (1−νE,P)2, where νE,P is the volume fraction of loose chain ends, plasticizer, or both. This effect is much larger than predicted by present theory. Also the equilibrium volume swelling ratio, V0/V, of rubbers having terminal chains or an equal volume of plasticizer is the same, provided they do not differ in crosslink density. However, the volume fraction of “network rubber” in the equilibrium swollen specimen, ν2, differs owing to the non-extractability of terminal chains. On this basis a method is proposed which allows experimental determination of the volume fraction of loose ends. Elastomers abounding in loose chain ends show markedly less long term stress relaxation. This effect is not clearly understood but is useful to detect the presence of non load-bearing network.

scholarly journals Semi-Crystalline Copolymer Hydrogels as Smart Drug Carriers: In Vitro Thermo-Responsive Naproxen Release Study

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 158
Author(s):  
Snežana Ilić-Stojanović ◽  
Ljubiša Nikolić ◽  
Vesna Nikolić ◽  
Slobodan Petrović ◽  
Violeta Oro ◽  
...  
Keyword(s):  
Drug Carrier ◽  
Drug Carriers ◽  
Xrd Analysis ◽  
Hplc Method ◽  
Potential Candidate ◽  
Swelling Kinetic ◽  
Model Drug ◽  
Xrd Techniques ◽  
Responsive Hydrogels

In this study, poly(N-isopropylacrylamide-co-2-hydroxypropyl methacrylate) hydrogels were synthesized using free radical initiated copolymerization method. Four hydrogels with different cross-linker concentrations were prepared. Semi-crystalline, cross-linked copolymer networks were confirmed by FTIR, SEM and XRD analysis. Variation of swelling behaviour was monitored gravimetrically and thermo-responsiveness has been noticed. An application of synthesized thermo-responsive hydrogels as carriers for the modulated release of anti-inflammatory model drug was investigated. Moreover, naproxen loading into these hydrogels was also determined using FTIR, SEM and XRD techniques and release was analyzed using HPLC method at simulated physiological conditions. Swelling kinetic and mechanism of water transport, as well as diffusion of naproxen through the hydrogels were analyzed. Thus, the aim of this work was to study various compositions of obtained hydrogels and their possibility of application as a thermo-responsive carrier for prolonged naproxen release in order to evaluate as a potential candidate for drug carrier in future pharmaceutical applications.

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