Soft Matter Characterization

doi:10.1007/978-1-4020-4465-6

Cited by 107 publications

(5 citation statements)

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“…The relaxation times, τ , were calculated for each of the samples by fitting the exponent β using a non-linear least squares algorithm. system with local or microscopic stresses [46,47]. For Films 1 and 2, the behavior of the exponent β suggests a large-scale stress release into a glassy state through crystalline domain redistribution, possibly through domain re-orientation and translational motions [48],…”

Section: Resultsmentioning

confidence: 99%

Stress relaxation in quasi-two-dimensional self-assembled nanoparticle monolayers

et al. 2018

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We experimentally probed the stress relaxation of a monolayer of iron oxide nanoparticles at the water-air interface. Upon drop-casting onto a water surface, the nanoparticles self-assembled into islands of two-dimensional hexagonally close packed crystalline domains surrounded by large voids. When compressed laterally, the voids gradually disappeared as the surface pressure increased. After the compression was stopped, the surface pressure (as measured by a Wilhelmy plate) evolved as a function of the film aging time with three distinct timescales. These aging dynamics were intrinsic to the stressed state built up during the non-equilibrium compression of the film. Utilizing x-ray photon correlation spectroscopy, we measured the characteristic relaxation time (τ) of in-plane nanoparticle motion as a function of the aging time through both second-order and two-time autocorrelation analysis. Compressed and stretched exponential fitting of the intermediate scattering function yielded exponents (β) indicating different relaxation mechanisms of the films under different compression stresses. For a monolayer compressed to a lower surface pressure (between 20 mN/m and 30 mN/m), the relaxation time (τ) decreased continuously as a function of the aging time, as did the fitted exponent, which transitioned from being compressed (>1) to stretched (<1), indicating that the monolayer underwent a stress release through crystalline domain reorganization. However, for a monolayer compressed to a higher surface pressure (around 40 mN/m), the relaxation time increased continuously and the compressed exponent varied very little from a value of 1.6, suggesting that the system may have been highly stressed and jammed. Despite the interesting stress relaxation signatures seen in these samples, the structural ordering of the monolayer remained the same over the sample lifetime, as revealed by grazing incidence x-ray diffraction.

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Section: Resultsmentioning

confidence: 99%

Stress relaxation in quasi-two-dimensional self-assembled nanoparticle monolayers

et al. 2018

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“…Accurate predictions of cell volume changes in response to pressure challenges can help to quantify the mechanical behavior of living cells and contributes to the understanding and diagnosis of various pathologies ( Liu et al, 2019a , 2019b ). More importantly, such a predictive model can help to accelerate biomedical drug discovery and clinical research into novel cancer treatments, as well as advancing other fields such as bioengineering and tissue regeneration, drug delivery, hygiene products, and microfluidic organ-on-chip technologies ( Borsali and Pecora, 2008 ; Feksa et al, 2018 ; Whelan et al, 2021 ). In the present work, we used the finite element method to simulate the osmotic-driven swelling and deswelling kinetics of the cytoplasm of a living cell.…”

Section: Discussionmentioning

confidence: 99%

Poroelastic osmoregulation of living cell volume

et al. 2021

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Summary Cells maintain their volume through fine intracellular osmolarity regulation. Osmotic challenges drive fluid into or out of cells causing swelling or shrinkage, respectively. The dynamics of cell volume changes depending on the rheology of the cellular constituents and on how fast the fluid permeates through the membrane and cytoplasm. We investigated whether and how poroelasticity can describe volume dynamics in response to osmotic shocks. We exposed cells to osmotic perturbations and used defocusing epifluorescence microscopy on membrane-attached fluorescent nanospheres to track volume dynamics with high spatiotemporal resolution. We found that a poroelastic model that considers both geometrical and pressurization rates captures fluid-cytoskeleton interactions, which are rate-limiting factors in controlling volume changes at short timescales. Linking cellular responses to osmotic shocks and cell mechanics through poroelasticity can predict the cell state in health, disease, or in response to novel therapeutics.

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“…The radial average of SAXS intensity as a function of q is shown in Figure 4E. The lamellar morphology of triblock copolymer is confirmed by the multiple orders of Bragg peaks at the relative positions of 1:2:3:4:5 (Borsali and Pecora, 2008). The estimated size of microdomain is 30 nm ( =2π q m ), as calculated from the position of the first Bragg peak at q m = 0.21 nm −1 .…”

Section: Morphologymentioning

confidence: 81%

Polyethylene Glycol-Modified Poly(Styrene-co-Ethylene/Butylene-co-Styrene)/Carbon Nanotubes Composite for Humidity Sensing

et al. 2019

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Polymeric composites of the linear triblock copolymer poly(styrene-co-ethylene/butylene-co-styrene) grafted with maleic anhydride units (SEBS-MA) or MA modified by hydrophilic polyethylene glycol (PEG) and containing various amounts of multiwall carbon nanotubes (MWCNTs) as conducting filler-were prepared by solvent casting. The MWCNT surface was modified by a non-covalent approach with a pyrene-based surfactant to achieve a homogeneous dispersion of the conducting filler within the polymeric matrix. The dispersion of the unmodified and surfactant-modified MWCNTs within the elastomeric SEBS-MA and SEBS-MA-PEG matrices was characterized by studying the morphology by TEM and SAXS. Dynamical mechanical analysis was used to evaluate the interaction between the MWCNTs and copolymer matrix. The electrical conductivity of the prepared composites was measured by dielectric relaxation spectroscopy, and the percolation threshold was calculated. The prepared elastomeric composites were characterized and studied as humidity sensor. Our results demonstrated that at MWCNTs concentration slightly above the percolation threshold could result in large signal changes. In our system, good results were obtained for MWCNT loading of 2 wt% and an ∼0.1 mm thin composite film. The thickness of the tested elastomeric composites and the source current appear to be very important factors that influence the sensing performance.

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Soft Matter Characterization

Cited by 107 publications

References 0 publications

Stress relaxation in quasi-two-dimensional self-assembled nanoparticle monolayers

Stress relaxation in quasi-two-dimensional self-assembled nanoparticle monolayers

Poroelastic osmoregulation of living cell volume

Polyethylene Glycol-Modified Poly(Styrene-co-Ethylene/Butylene-co-Styrene)/Carbon Nanotubes Composite for Humidity Sensing

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