Strain hardening and highly resilient hydrogels crosslinked by chain-extended reactive pseudo-polyrotaxane

Cui, Yulin; Tan, Mei; Zhu, Aidi; Guo, Mingyu

doi:10.1039/c4ra10928g

Cited by 22 publications

(22 citation statements)

References 40 publications

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“…Considering the same applied force in all cases, the promoted higher crosslinked network from higher dose enhances strength and resistance to deformation, together with the associated decrease in the extensibility. 32,33 On the contrary, Extension 2 is related to the contraction of the sample, following Hooke's law and therefore determined by the value of the Young's modulus (equation 5), where r is the stress, e is the strain, F is the applied force, A is the area of the sample (width 3 thickness), l 0 is the initial length of the sample, and dl is the change in length (the displacement, the extension).…”

Section: Discussionmentioning

confidence: 97%

Connecting free volume with shape memory properties in noncytotoxic gamma‐irradiated polycyclooctene

Axpe

García-Huete

Cuevas

et al. 2015

J Polym Sci B Polym Phys

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ABSTRACT:The free volume holes of a shape memory polymer have been analyzed considering that the empty space between molecules is necessary for the molecular motion, and the shape memory response is based on polymer segments acting as molecular switches through variable flexibility with temperature or other stimuli. Therefore, thermomechanical analysis (TMA) and positron annihilation lifetime spectroscopy (PALS) have been applied to analyze shape recovery and free volume hole sizes in gamma-irradiated polycyclooctene (PCO) samples, as a noncytotoxic alternative to more conventional PCO crosslinked via peroxide for future applications in medicine. Thus, a first approach relating structure, free volume holes and shape memory properties in gamma-irradiated PCO is presented. The results suggest that free volume holes caused by gamma irradiation in PCO samples facilitate the recovery process by improving movement of polymer chains and open possibilities for the design and control of the macroscopic response. V C 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 1080-1088 KEYWORDS: free volume; gamma-irradiated polycylooctene; noncytotoxic polymers; positron annihilation lifetime spectroscopy; shape memory polymers INTRODUCTION Polycyclooctene (PCO) is a semicrystalline polymer that can be obtained by ring-opening metathesis polymerization (ROMP), and demonstrates outstanding shape memory properties by crosslinking the macromolecular chains. Employing commercial PCO, magneto-active polymers, 1 thermoresponsive polymers, 2 shape memory composites, 3 triple-shape memory polymers, 4 and selfrepair systems 5 have been developed. Based on the reversibility of the effect, shape memory polymers are categorized in one-way SMPs (1W-SMPs) and two-way SMPs (2W-SMPs). In the first case, 1W-SMPs, after the recovery process, it is necessary to program again the material to obtain a new transition between the temporary and the permanent shape. In the second case, 2W-SMPs, the transition between the temporary shape and the permanent one is reversible (reversing the supplied stimulus, temporary or permanent shape can be obtained). As it has been previously described, 6-9 PCO has shown both effects.

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Section: Discussionmentioning

confidence: 97%

Connecting free volume with shape memory properties in noncytotoxic gamma‐irradiated polycyclooctene

Axpe

García-Huete

Cuevas

et al. 2015

J Polym Sci B Polym Phys

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“…Plu‐N was synthesized through activating hydroxyl of Pluronic using CDI followed by conjugating ethylenediamine in the terminal groups as described in the previous report . Briefly, the solution of CDI (0.405 g, 2.5 mmol) in 5 mL of tetrahydrofuran (THF) was added dropwise to the solution of Pluronic F127 (Plu, 3.15 g, 0.25 mmol) in 10 mL of THF for 30 min at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Surface Charge Reversible Polymeric Micelle‐Laden Hydrogels for Drug Delivery and 3D Cell Culture

Wang

Zhang

Jiang

et al. 2018

Macro Chemistry & Physics

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Hydrogels have significant advantages in the local treatment of diseases. However, improving the solubility of hydrophobic drugs and enhancing cell targeting of drug delivery remain significant challenges in the application of such hydrogels. Surface charge reversible polymeric micelle‐laden hydrogels are developed for drug delivery and 3D cell culture. Borax is added into the system to form borate with hydroxyl groups of alginate for rapid gelation. Decreasing pH surrounding the hydrogels facilitates the degradation of the hydrogels and charge reversal of polymeric micelles. The negative‐to‐positive charge reversal endows polymeric micelles with cell targeting and enhanced cell uptake of polymeric micelles. A potential and effective in situ drug delivery system for the local treatment of diseases is provided.

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“…After the LVR, G′ increases slightly with the shear strain until it reaches the critical strain of rupture, indicating a more rapidly rising stress relative to increasing straina hardening behavior (Fig. Strain hardening properties are frequently observed in biopolymer gels 42,43 and interpenetrating networks (IPNs), 44,45 where weak crosslinks break up for the sake of dissipating energy. In the figure, the upturn of G″ is even more significant.…”

Section: In Situ Gelation and Rheological Measurementsmentioning

confidence: 99%

“…5b). 42,43 The dynamic disulfide bonds play a key role in energy dissipation, and are possibly responsible for the large rupture strain and strain hardening behavior observed in the synthesized hydrogels. Strain hardening properties are frequently observed in biopolymer gels 42,43 and interpenetrating networks (IPNs), 44,45 where weak crosslinks break up for the sake of dissipating energy.…”

Section: In Situ Gelation and Rheological Measurementsmentioning

confidence: 99%

Reductant-triggered rapid self-gelation and biological functionalization of hydrogels

Chen

Wu²,

Cheng³

et al. 2015

Polym. Chem.

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Hydrogels have found wide applications in many fields. Although plenty of mature preparation methodologies are available now, there is certainly a continuous impetus in developing new methods toward simplicity, adjustability and satisfying diverse emerging needs. In this paper, a novel and efficient approach for hydrogel preparation is proposed. Polyacrylamide (PAM) chains with pyridyl disulfide (PDS) side groups were synthesized by free-radical polymerization. Upon addition of a tiny amount of reductants to the aqueous solution of the synthesized copolymer, part of the PDS groups are reduced to free thiols, and the subsequent exchange reaction between thiol groups and PDS results in disulfide-crosslinked hydrogels. The rapid self-gelation process was monitored by in situ rheological measurements, and the network structures of the hydrogels were observed using a scanning electron microscope. It has been found that the mechanical properties and pore sizes of the hydrogels could be tuned by changing the polymer concentration and the amounts of the reductants added into the solution. The residual PDS groups in the hydrogels provide reaction sites for immobilization of biological functional molecules.Reduced glutathione and bovine serum albumin were successfully immobilized in the hydrogels, and the bioactivities of the hydrogels were measured in this research. The disulfide crosslinks are cleavable and the hydrogels are dissociated under reducing conditions, which indicates that the hydrogels may find potential applications in biological and medical fields.Scheme 1 (a) Chemical reactions in the process of the reductanttriggered self-gelation; (b) illustration of the self-gelation and post-functionalization process. PaperPolymer ChemistryPolym. Chem. This journal is

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Strain hardening and highly resilient hydrogels crosslinked by chain-extended reactive pseudo-polyrotaxane

Abstract: Hydrogels with obvious strain hardening and high resilience properties in both stretching and compressing processes are constructed by simple free-radical copolymerization of acrylamide and reactive pseudo-polyrotaxane.

Cited by 22 publications

References 40 publications

Connecting free volume with shape memory properties in noncytotoxic gamma‐irradiated polycyclooctene

Connecting free volume with shape memory properties in noncytotoxic gamma‐irradiated polycyclooctene

Surface Charge Reversible Polymeric Micelle‐Laden Hydrogels for Drug Delivery and 3D Cell Culture

Reductant-triggered rapid self-gelation and biological functionalization of hydrogels

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