Interaction of phenols with thermo-responsive hydrogels

Kosik, Katalin; Wilk, E.; Geissler, Erik; László, Krisztina

doi:10.1016/j.colsurfa.2007.07.022

Cited by 12 publications

(13 citation statements)

References 19 publications

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“…Finally, equilibrium swelling diagrams are approximated on a series of PNIPA gels with various molar fractions of cross‐linker c cr (the ratios of molar fractions of cross‐linker m cr to that of monomers m mon in a pre‐gel solutions). The gels are prepared by free‐radical cross‐linking polymerization (at temperature 20°C) of aqueous solutions of NIPA monomers (0.75 M) by using BIS (molar fractions ranged from 3.75 to 10 mM) as a cross‐linker, APS as an initiator and TEMED as an accelerator 54 …”

Section: Comparison With Experimental Datamentioning

confidence: 99%

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Equilibrium swelling of thermo‐responsive core‐shell microgels

Drozdov

Christiansen

2020

J of Applied Polymer Sci

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Design of new routes for preparation of hydrogels with fast response and enhanced mechanical and physical properties requires adequate modeling of their swelling. A model is developed for the equilibrium swelling of thermo‐responsive gels. A characteristic feature of the model is that it accounts for a strong increase in the elastic moduli above the volume phase transition temperature Tc driven by aggregation of hydrophobic segments into clusters that serve as extra physical bonds between chains. The model is applied to the analysis of swelling diagrams on poly(N‐isopropylacrylamide) macroscopic gels, microgel latices, and core‐shell microgels with rigid cores. Good agreement is shown between the experimental data and results of simulation. It is demonstrated that the elastic moduli of microgels are higher, while their degrees of swelling in the stress‐free state are lower compared with those of macroscopic gels.

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Section: Comparison With Experimental Datamentioning

confidence: 99%

“…Degree of swelling Q versus temperature T . Circles: Experimental data 54 on PNIPA gels with various molar fractions of cross‐linker c cr mol%. (a) c cr = 0.5, (b) c cr = 0.67, (c) c cr = 1.0, (d) c cr = 1.33.…”

Section: Comparison With Experimental Datamentioning

confidence: 99%

Equilibrium swelling of thermo‐responsive core‐shell microgels

Drozdov

Christiansen

2020

J of Applied Polymer Sci

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“…Of particular interest is the study of Hirotsu et al [14], which showed that at neutral pH, NIPAM-acrylic acid copolymer gels undergo a discontinuous transition as a function of temperature above a certain acrylic acid content. For the PNIPAM gels described here, the transition is continuous [54]. This condition sets an upper limit for their intrinsic ionic content of about 0.1%.…”

Section: Acid and Base Solutionsmentioning

confidence: 99%

Search for the Origin of Discrepancies in Osmotic Measurements of the PNIPAM - Water System

Manek

Tombácz

Geissler

et al. 2017

Period. Polytech. Chem. Eng.

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“…In our previous publications the influence of phenol, resorcinol and phloroglucinol, studied by scattering, calorimetric and later by NMR techniques were reported in detail (12)(13)(14)19). It was found earlier that they exhibit an interaction with the polymer chains that depends on the number of the OH-groups [19].…”

Section: Introductionmentioning

confidence: 99%

“…It was found earlier that they exhibit an interaction with the polymer chains that depends on the number of the OH-groups [19]. Binding of phenol to PNIPA is mediated by hydrogen bonds between the amide group of the NIPA chain and the hydroxyl group of the phenol molecule [20].…”

Section: Introductionmentioning

confidence: 99%

Interactions in aromatic probe molecule loaded poly(N-isopropylacrylamide) hydrogels and implications for drug delivery

Manek

Domján

Madarász

et al. 2015

European Polymer Journal

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Small aromatic molecules are known to interact with poly(N-isopropylacrylamide) (PNIPA) based hydrogels, one of the most frequently employed polymers in temperature induced drug delivery systems. These interactions are poorly understood at the molecular level. In this article we investigate PNIPA both at the macroscopic and at the molecular level using measurements of swelling, differential scanning microcalorimetry (DSC), X-ray powder diffraction (XRD) and solid state 1 H NMR methods. The nature and the strength of the interactions affect the efficiency and kinetics of drug delivery. Phenols exert a major influence on PNIPA by reducing its phase transition temperature. The effect depends linearly on the phenol concentration, and is influenced also by the number of phenolic OH groups, as well as their relative positions. The strong interaction between phenol and the polymer that is detected by NMR hinders the crystallisation of phenol when the water is gradually evaporated. The aminoethyl phenol derivative dopamine has a much more limited effect, but in the opposite direction -the transition temperature increases slightly. The strong interaction observed among the dopamine molecules disables the polymer -dopamine interaction and favours crystallization of the dopamine when water is removed. These results reveal that embedding the drugs into polymer matrices for controlled delivery can alter the crystallinity of the stored molecules. As morphology is one of the crucial factors in delivery, this may compromise the rate and the efficiency of release.

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Interaction of phenols with thermo-responsive hydrogels

Cited by 12 publications

References 19 publications

Equilibrium swelling of thermo‐responsive core‐shell microgels

Equilibrium swelling of thermo‐responsive core‐shell microgels

Search for the Origin of Discrepancies in Osmotic Measurements of the PNIPAM - Water System

Interactions in aromatic probe molecule loaded poly(N-isopropylacrylamide) hydrogels and implications for drug delivery

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