Investigation of translational motion of poly(ethylene glycol) macromolecules in poly(methacrylic acid) hydrogels

Abstract

SUMMARY: The translational mobility of linear macromolecules of poly(ethylene glycol) (PEG) within a weakly cross-linked poly(methacrylic acid) (PMAA) hydrogel was investigated by means of the pulse field gradient (PFG) NMR method in order to reveal the effect of PMAA/PEG complex formation. It was found that inside the collapsed gel a fraction of the PEG molecules has self-diffusion characteristics like those of the network chains. This suggests the formation of an interpolymer complex, as a result of which some linear molecules acquired the dynamic properties of the network chains. Another fraction of the PEG macromolecules inside the collapsed gel enjoyed free diffusion, for they were not included in the complex with PMAA. In contrast, within the swollen gel (at concentrations of PEG higher than 5 wt.-%) the self-diffusion coefficient of all PEG molecules was independent of the diffusion time, which indicates an absence of the interpolymer complex (or at least that its lifetime is negligibly short).

Rodlike polymer gelatination as studied by PFG NMR: Fibrin polymerization in human plasma

“…Nevertheless, such molecules can be fixed indirectly by registration Prs < 1, the same as in refs. 3 …”

“…10 The appearance of the SDC spectrum during polymerization was observed earlier by studying gelatination in some systems [2,3,26]. Such spectrum is a characte¡ feature of a polymerization process.…”

“…One of the promising methods to study molecular mechanisms of fibrin polymerization is the PFG (pulse field gradient) NMR (nuclear magnetic resonance) method. Its possibilities were demonstrated earlier by the example of systems like radiationally cross-linked polybutadiens [1], water solutions of gelatin [2], hydrogels of polymethacrylic acid [3].…”

“…To investigate the supermolecular structure formation (self-organization) in polymer and biopolymer systems becomes very urgent recently [1][2][3][4]. The importance to investigate polymer systems able to change their properties under external influence (network structure formation, collapse-decollapse transition, etc.)…”

Interpolymer complexes of poly(acrylic acid) nanogels with some non-ionic polymers in aqueous solutions

“…The next step in the development of this field was the study of interpolymer interactions, in which one of the polymeric reagents is represented by a gel, i.e. three-dimensional polymeric network swollen in aqueous or organic solvent [6][7][8][9][10]. In this case the interaction proceeds through the penetration of linear macromolecules into polymeric hydrogel and complexation with the network segments, which is accompanied by a volume-phase transition of the samples.…”