Dynamics of entangled supramolecular polymer networks in presence of high‐order associations of strong hydrogen bonding groups

Jangizehi, Amir; Ghaffarian, Seyed Reza; Ahmadi, Mostafa

doi:10.1002/pat.4178

Cited by 21 publications

(36 citation statements)

References 89 publications

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“…These results indicate that, depending on the utilized ion, supramolecular assemblies larger than what is expected from a simple binary association can form. Such behavior has been frequently reported for supramolecular polymer systems in melt and it has been associated with different polarity of polymer backbone and supramolecular motifs . In our hydrogel system, however, it can be speculated that the formation of nanoscopic clusters can be mediated by Coulomb interactions between the charged bis‐complexes in the gel and the counter ions in their vicinity .…”

Section: Resultssupporting

confidence: 58%

Dynamic Model Metallo‐Supramolecular Dual‐Network Hydrogels with Independently Tunable Network Crosslinks

Ahmadi

Seiffert

2020

Journal of Polymer Science

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Hybrid polymer networks emerge between chemical and physical crosslinking, where two different modes of chain connectivity control the material behavior. However, rational relations between their microstructural characteristics, supramolecular kinetics, and the resulting network mechanics and dynamics are not well developed. To address this shortcoming, this study introduces a material platform based on a model dual-network hydrogel, comprising independently tunable chemical and physical crosslinks. The idea is realized by a click reaction between a tetra-PEG and a linear-PEG precursor, whereby the linear block also carries a terpyridine ligand at each end that can form additional physical crosslinks by metal ion-bis(terpyridine) complexation. We change the number of chemical crosslinks by varying the molar mass of the tetra-PEG, and we independently tune the metallo-supramolecular bonds by using different metal ions, Mn 2+ , Zn 2+ , Co 2+ , and Ni 2+ . Based on that modular approach, we study the rheological behavior and the diffusivity of fluorescent polymeric tracers. The dissociation of the metallosupramolecular bonds provides a relaxation step, whose timescale and intensity are quantified by a sticky Rouse model. These two characteristics differ not only depending on the metal ion but also according to the chemical network mesh size, which highlights an interplay between the chemical and physical crosslinks.

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Section: Resultssupporting

confidence: 58%

Dynamic Model Metallo‐Supramolecular Dual‐Network Hydrogels with Independently Tunable Network Crosslinks

Ahmadi

Seiffert

2020

Journal of Polymer Science

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“…A versatile principle for obtaining supramolecular associative polymer networks is through transient linkage of associative side motifs, often named “stickers,” that are distributed randomly along covalently jointed polymer chains . We denote this type of supramolecular associative polymer networks as side‐supra networks .…”

Section: Introductionmentioning

confidence: 99%

Dynamics of supramolecular associative polymer networks at the interplay of chain entanglement, transient chain association, and chain‐sticker clustering

Jangizehi

Ahmadi

Seiffert

2019

J Polym Sci B Polym Phys

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The dynamic mechanical properties of supramolecular associative polymer networks depend on the average number of entanglements along the network-forming chains, N e , and on their content of associative groups, f. In addition, there may be further influence by aggregation of the associative groups into clusters, which, in turn, is influenced by the chemical structure of these groups, and again by N e and f of the polymer. Therefore, the effects of these parameters are interdependent. To conceptually understand this interdependency, we study model networks in which (a) N e , (b) f, and (c) the chemical structure of the associative groups are varied systematically. Each network is probed by rheology. The clustering of the associative groups is assessed by analyzing the rheological data at the end range of frequency covered and by comparison of the number of supramolecular network junctions with the maximum possible number of binary transient bonds. We find that if the total number of the network junctions, which can be formed either by interchain entanglement or by interchain transient associations, is greater than a threshold of 13, then the likelihood of cluster formation is high and the dynamics of supramolecular associative polymer networks is mainly controlled by this phenomenon.

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“…Other methods of gelation include those that exploit the largely entropically based hydrophobic force, induce crystallization of a single component across the phase, or percolate a network via polymer entanglements . We refer to the latter two processes as supramolecular‐like, as physical, noncovalent interactions contribute to the formation of a network, but not necessarily via strictly defined supramolecular interactions (crystallization, entanglement).…”

Section: Molecular Mechanisms Of Gelationmentioning

confidence: 99%

Gels without Vapor Pressure: Soft, Nonaqueous, and Solvent‐Free Supramolecular Biomaterials for Prospective Parenteral Drug Delivery Applications

Tabet

Wang

2018

Adv Healthcare Materials

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now making up 90% of the drugs in development. [9] Since hydrogel matrices are predominantly hydrophilic with high water content, there may be limits in loading clinically relevant concentrations of poorly water-soluble APIs and achieving bolus-free, prolonged, zero or first-order release kinetics of these drugs over several weeks. [11] Further challenges include the mechanical fragility of many biodegradable hydrogels, dehydration over time, and nonideal drug release due to leakage or phase separation. [12] Although mechanical weaknesses of hydrogels may be overcome by several approaches such as introducing a second interpenetrating supramolecular or covalent network within the primary hydrogel matrix, [13] other problems due to the inherent presence of water have no straightforward remedy.Given these current limitations in hydrogel technology, in particular those associated with the incompatibility of aqueous matrices with controlled release of poorly soluble drugs, some groups have explored whether nonaqueous matrices can overcome these challenges. [14,15] One alternative class of materials to hydrogels is organogels. A typical organogel is composed of a hydrophobic or amphiphilic gelator and an organic solvent, such as N-methyl-2-pyrrolidone (NMP) or dimethyl sulfoxide (DMSO). [3] A common strategy for the use of organogels in parenteral drug delivery is direct injection of polymer mixed with drug and added organic solvent for solubilization and viscosity reduction. Subsequent solvent leeching results in the formation of an implant in situ to release the drug over time. [14] However, compelling reasons against the clinical adoption of such materials exist, including the concern over safety of injecting organic-solvent loaded materials into patients with potentially harmful or unknown biological consequences. [3,16] A highly promising subset of organogels that has seen limited adoption into drug delivery is called oleogels, which do not contain organic solvents, such as NMP, and consist of oligomers or polymer oils/melts. [8] These materials are supramolecular analogues to soft, covalent elastomers. A key advantage of such polymer melt-based gels is their lack of any appreciable vapor pressure. [17] Such stability and lack of evaporation over time makes these materials quite distinct from hydrogels or organic solvent-based organogels. Whereas hydrogels can be left sealed on the benchtop or in the fridge and remain unaltered due to evaporation on the order of days, solvent-free gels are potentially stable for months to years. While the application of these The engineering advantages of soft, nonaqueous, solvent-free supramolecular materials have resulted in their emerging transition and adoption from a predominantly food, cosmetics, and paint industry-driven technology to biocompatible matrices for parenteral drug delivery. Factors that have contributed to this trend are the drastic increase of hydrophobic and combination drugs in the pharmaceutical pipeline and the limitations of hydrated drug delivery materia...

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Dynamics of entangled supramolecular polymer networks in presence of high‐order associations of strong hydrogen bonding groups

Cited by 21 publications

References 89 publications

Dynamic Model Metallo‐Supramolecular Dual‐Network Hydrogels with Independently Tunable Network Crosslinks

Dynamic Model Metallo‐Supramolecular Dual‐Network Hydrogels with Independently Tunable Network Crosslinks

Dynamics of supramolecular associative polymer networks at the interplay of chain entanglement, transient chain association, and chain‐sticker clustering

Gels without Vapor Pressure: Soft, Nonaqueous, and Solvent‐Free Supramolecular Biomaterials for Prospective Parenteral Drug Delivery Applications

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