Mesoscale Characterization of Supramolecular Transient Networks Using SAXS and Rheology

Pape, Anna-Antonia; Bastings, Maartje M. C.; Kieltyka, Roxanne E.; Wyss, Hans M.; Voets, Ilja K.; Meijer, E. W.; Dankers, Patricia Y. W.

doi:10.3390/ijms15011096

Cited by 43 publications

(31 citation statements)

References 41 publications

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“…Time-temperature superposition (TTS) is widely used for classical polymer systems where the increase of temperature only impacts the rate of relaxation while the microstructure remains intact. [52][53][54] In previous studies of dynamic transient networks and associating polymer chains, [54][55][56] TTS can be achieved by using two shift factors, a T for frequency and b T for G′ and G″, where a T correlates the frequency (time) temperature relationship and b T accounts for the elastically active chains in the network. Interestingly, TTS was applicable for all three of the dynamic networks 2 0:100 , 2 20:80 , and 2 40:60 .…”

Section: Resultsmentioning

confidence: 99%

Impact of Dynamic Bond Concentration on the Viscoelastic and Mechanical Properties of Dynamic Poly(alkylurea‐co‐urethane) Networks

Chen

Zhang

Griffin

et al. 2019

Macro Chemistry & Physics

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Polymer networks containing dynamic covalent bonds do not exhibit traditional thermoset material properties. Such dynamic covalent networks have the ability to undergo stress relaxation processes associated with dynamic covalent bond exchange, imparting these materials with adaptive/responsive properties. Reported herein is an investigation on the effect that changing the amount of dynamic hindered alkylurea bonds has on the viscoelastic behavior of a series of poly(alkylurea‐co‐urethane) networks prepared by reacting a trifunctional isocyanate crosslinker with varying ratios of an N‐isopropyl amine endcapped poly(propylene glycol) and a poly(propylene glycol). Films that contain >50% dynamic alkylurea bonds (wrt. alkylurea + urethane bonds) exhibit facile reprocessability, while those films with <50% dynamic alkylurea bonds exhibit poor reprocessability under these same conditions. Analysis of the temperature‐dependent shear rheometry and uniaxial stress relaxation measurements demonstrates that the primary stress relaxation mode in these materials is linked to the dynamic bond exchange process. Interestingly, these films exhibit an increasingly rich viscoelastic spectrum with increasing fraction of non‐dynamic urethane bonds. In addition to the primary relaxation process an order‐of‐magnitude slower relaxation emerges, which is identified as being related to the relaxation of larger, permanently crosslinked polymeric clusters in an otherwise dynamic matrix.

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Section: Resultsmentioning

confidence: 99%

Impact of Dynamic Bond Concentration on the Viscoelastic and Mechanical Properties of Dynamic Poly(alkylurea‐co‐urethane) Networks

Chen

Zhang

Griffin

et al. 2019

Macro Chemistry & Physics

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“…The diffusion of this acid is probably the limiting factor in the gelation of the hydrogel in in vitro experiments; however, in vivo the liquid would have a high contact surface area with neutralizing tissue, which will most likely result in a faster and more evenly gelation compared to dropwise addition of concentrated acid. Moreover, the gel switching is much faster with this mild procedure as compared to previously used methods (0.5 hr vs 2 hr) 25 . Using the body's natural pH for switching of the material properties is very appealing since the transition is swift, reversible, cannot occur inside the catheter and is in vivo fully automatic.…”

Section: Discussionmentioning

confidence: 79%

An Injectable and Drug-loaded Supramolecular Hydrogel for Local Catheter Injection into the Pig Heart

Pape

Bakker

Tseng

et al. 2015

JoVE

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Regeneration of lost myocardium is an important goal for future therapies because of the increasing occurrence of chronic ischemic heart failure and the limited access to donor hearts. An example of a treatment to recover the function of the heart consists of the local delivery of drugs and bioactives from a hydrogel. In this paper a method is introduced to formulate and inject a drug-loaded hydrogel non-invasively and side-specific into the pig heart using a long, flexible catheter. The use of 3-D electromechanical mapping and injection via a catheter allows side-specific treatment of the myocardium. To provide a hydrogel compatible with this catheter, a supramolecular hydrogel is used because of the convenient switching from a gel to a solution state using environmental triggers. At basic pH this ureido-pyrimidinone modified poly(ethylene glycol) acts as a Newtonian fluid which can be easily injected, but at physiological pH the solution rapidly switches into a gel. These mild switching conditions allow for the incorporation of bioactive drugs and bioactive species, such as growth factors and exosomes as we present here in both in vitro and in vivo experiments. The in vitro experiments give an on forehand indication of the gel stability and drug release, which allows for tuning of the gel and release properties before the subsequent application in vivo. This combination allows for the optimal tuning of the gel to the used bioactive compounds and species, and the injection system.

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“…The incorporation of nanoparticles into the composites will affect the thermal and viscoelastic properties . Here, the samples containing 0, 2, 4, and 6 wt% of silica nanoparticles functionalized with UPy using the U5 matrix are investigated.…”

Section: Resultsmentioning

confidence: 99%

Improving microcellular foamability of amorphous supramolecular polymers via functionalized nanosilica particles

et al. 2017

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This work introduces and investigates a synergistic approach to tailor microcellular morphology and physical properties of soft polymer foams by simultaneously utilizing supramolecular associations and nanoparticle inclusions. For this purpose, supramolecular nanocomposite foams consisting of soft amorphous polyacrylates and silica nanoparticles are successfully prepared and characterized. The polymer precursors as well as the nanoparticles are all functionalized with ureido-pyrimidinone (UPy) supramolecular groups at various contents. Microcellular foams are produced in a batch process at 908C after a 5-h saturation step in 9 MPa, using supercritical N 2 as the physical foaming agent. The effects of UPy-grafting on microcellular morphology and consequently on thermal, viscoelastic, and mechanical properties is investigated. Dispersion of nanoparticles as well as the cellular structure of supramolecular nanocomposite foams is analyzed in relation to supramolecular moiety-grafting density. It is illustrated that strong quadrupole hydrogen bonding between the filler and matrix not only improves the degree of reinforcement in nanocomposites, but also stabilizes bubble growth and retards cell coalescence or rupture. An optimum average cell size and microcellular density, that is, 6 6 0.2 lm and 6 3 10 9 cells/cm 3 , respectively, is achieved with only 4 wt% UPyfunctionalized nanoparticle loading. These results illustrate, therefore, that supramolecular interactions between the chain backbone and nanoscale inclusions can open new horizons to architect and exploit microcellular materials consist up of amorphous, soft, loosely entangled polymers. POLYM. COMPOS., 00:000-000,

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Mesoscale Characterization of Supramolecular Transient Networks Using SAXS and Rheology

Cited by 43 publications

References 41 publications

Impact of Dynamic Bond Concentration on the Viscoelastic and Mechanical Properties of Dynamic Poly(alkylurea‐co‐urethane) Networks

Impact of Dynamic Bond Concentration on the Viscoelastic and Mechanical Properties of Dynamic Poly(alkylurea‐co‐urethane) Networks

An Injectable and Drug-loaded Supramolecular Hydrogel for Local Catheter Injection into the Pig Heart

Improving microcellular foamability of amorphous supramolecular polymers via functionalized nanosilica particles

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