Showing papers on "Elastic modulus published in 2012"
TL;DR: It is concluded that stem cells exert a mechanical force on collagen fibres and gauge the feedback to make cell-fate decisions, and are regulated by the elastic modulus of PAAm.
Abstract: To investigate how substrate properties influence stem-cell fate, we cultured single human epidermal stem cells on polydimethylsiloxane (PDMS) and polyacrylamide (PAAm) hydrogel surfaces, 0.1 kPa-2.3 MPa in stiffness, with a covalently attached collagen coating. Cell spreading and differentiation were unaffected by polydimethylsiloxane stiffness. However, cells on polyacrylamide of low elastic modulus (0.5 kPa) could not form stable focal adhesions and differentiated as a result of decreased activation of the extracellular-signal-related kinase (ERK)/mitogen-activated protein kinase (MAPK) signalling pathway. The differentiation of human mesenchymal stem cells was also unaffected by PDMS stiffness but regulated by the elastic modulus of PAAm. Dextran penetration measurements indicated that polyacrylamide substrates of low elastic modulus were more porous than stiff substrates, suggesting that the collagen anchoring points would be further apart. We then changed collagen crosslink concentration and used hydrogel-nanoparticle substrates to vary anchoring distance at constant substrate stiffness. Lower collagen anchoring density resulted in increased differentiation. We conclude that stem cells exert a mechanical force on collagen fibres and gauge the feedback to make cell-fate decisions.
1,393 citations
TL;DR: The development of new metallic alloys for biomedical applications is described in this paper, which includes β-type titanium alloys with a self-tunable modulus, which has been proposed for the construction of removable implants.
1,154 citations
TL;DR: In this article, a comprehensive review of the current state of the art of the study of elastic properties, the establishments of correlations between elastic moduli and properties/features, and the elastic models and elastic perspectives of metallic glasses is presented.
1,070 citations
TL;DR: The histological investigation concluded that there is a definite correlation between the orientation of the Langer lines and the preferred orientation of collagen fibres in the dermis and the data obtained will provide essential information for those wishing to model the skin using a structural constitutive model.
Abstract: The mechanical properties of skin are important for a number of applications including surgery, dermatology, impact biomechanics and forensic science. In this study, we have investigated the influence of location and orientation on the deformation characteristics of 56 samples of excised human skin. Uniaxial tensile tests were carried out at a strain rate of 0.012 s(-1) on skin from the back. Digital Image Correlation was used for 2D strain measurement and a histological examination of the dermis was also performed. The mean ultimate tensile strength (UTS) was 21.6±8.4 MPa, the mean failure strain 54%±17%, the mean initial slope 1.18±0.88 MPa, the mean elastic modulus 83.3±34.9 MPa and the mean strain energy was 3.6±1.6 MJ/m(3). A multivariate analysis of variance has shown that these mechanical properties of skin are dependent upon the orientation of the Langer lines (P<0.0001-P=0.046). The location of specimens on the back was also found to have a significant effect on the UTS (P=0.0002), the elastic modulus (P=0.001) and the strain energy (P=0.0052). The histological investigation concluded that there is a definite correlation between the orientation of the Langer lines and the preferred orientation of collagen fibres in the dermis (P<0.001). The data obtained in this study will provide essential information for those wishing to model the skin using a structural constitutive model.
562 citations
TL;DR: Polydimethylsiloxane (PDMS) blends could be used as the basis of a tunable system where the elastic modulus could be adjusted to match most types of soft tissue and can be controlled independently of other materials properties including surface roughness, surface energy and the ability to functionalize the surface by protein adsorption and microcontact printing.
Abstract: Mechanics is an important component in the regulation of cell shape, proliferation, migration and differentiation during normal homeostasis and disease states. Biomaterials that match the elastic modulus of soft tissues have been effective for studying this cell mechanobiology, but improvements are needed in order to investigate a wider range of physicochemical properties in a controlled manner. We hypothesized that polydimethylsiloxane (PDMS) blends could be used as the basis of a tunable system where the elastic modulus could be adjusted to match most types of soft tissue. To test this we formulated blends of two commercially available PDMS types, Sylgard 527 and Sylgard 184, which enabled us to fabricate substrates with an elastic modulus anywhere from 5 kPa up to 1.72 MPa. This is a three order-of-magnitude range of tunability, exceeding what is possible with other hydrogel and PDMS systems. Uniquely, the elastic modulus can be controlled independently of other materials properties including surface roughness, surface energy and the ability to functionalize the surface by protein adsorption and microcontact printing. For biological validation, PC12 (neuronal inducible-pheochromocytoma cell line) and C2C12 (muscle cell line) were used to demonstrate that these PDMS formulations support cell attachment and growth and that these substrates can be used to probe the mechanosensitivity of various cellular processes including neurite extension and muscle differentiation.
473 citations
TL;DR: In this article, the applicability of transversely isotropic model was quantitatively investigated on three rock types found in Korea and the experiments were conducted on rock specimen obtained from the directional coring system.
327 citations
TL;DR: It is demonstrated that a quantitative mapping of the elastic modulus of polymeric materials is possible and the JKR model should be used for the samples considered here instead of the DMT model, currently implemented in HarmoniX and PeakForce QNM modes.
Abstract: The modulus of elasticity of soft materials on the nanoscale is of interest when studying thin films, nanocomposites, and biomaterials Two novel modes of atomic force microscopy (AFM) have been introduced recently: HarmoniX and PeakForce QNM Both modes produce distribution maps of the elastic modulus over the sample surface Here we investigate the question of how quantitative these maps are when studying soft materials Three different polymers with a macroscopic Young’s modulus of 06–07 GPa (polyurethanes) and 27 GPa (polystyrene) are analyzed using these new modes The moduli obtained are compared to the data measured with the other commonly used techniques, dynamic mechanical analyzer (DMA), regular AFM, and nanoindenter We show that the elastic modulus is overestimated in both the HarmoniX and PeakForce QNM modes when using regular sharp probes because of excessively overstressed material in the samples We further demonstrate that both AFM modes can work in the linear stress–strain regime when
315 citations
TL;DR: In this paper, the Young's modulus of graphene is estimated by measuring the strain applied by a pressure difference across graphene membranes using Raman spectroscopy, which can be estimated directly from the peak shift of the Raman G band.
Abstract: The Young’s modulus of graphene is estimated by measuring the strain applied by a pressure difference across graphene membranes using Raman spectroscopy. The strain induced on pressurized graphene balloons can be estimated directly from the peak shift of the Raman G band. By comparing the measured strain with numerical simulation, we obtained the Young’s modulus of graphene. The estimated Young’s modulus values of single- and bilayer graphene are 2.4 ± 0.4 and 2.0 ± 0.5 TPa, respectively.
285 citations
TL;DR: In this article, the mechanical properties, in vitro degrades and cytotoxicity of Mg-4.0Zn-0.2Ca alloy were studied and it was revealed that the addition of Zn and Ca into Mg matrix could enhance the corrosion potential and reduced the degradation rate.
269 citations
TL;DR: In this article, the authors investigated the mechanical behavior of two-dimensional hierarchical honeycomb structures using analytical, numerical and experimental methods, and provided insight into the role of structural organization and hierarchy in regulating the mechanical behaviour of materials, and new opportunities for developing lowweight cellular structures with tailorable properties.
262 citations
TL;DR: The difference of three orders of magnitude observed in the moduli of fiber scaffolds vs. single fibers can be explained by the lacunar and random structure of the scaffolds.
TL;DR: Ti-6Al-4V alloy with two kinds of open cellular structures of stochastic foam and reticulated mesh was fabricated by additive manufacturing (AM) using electron beam melting (EBM), and microstructure and mechanical properties of these samples with high porosity were investigated.
Abstract: Ti-6Al-4V alloy with two kinds of open cellular structures of stochastic foam and reticulated mesh was fabricated by additive manufacturing (AM) using electron beam melting (EBM), and microstructure and mechanical properties of these samples with high porosity in the range of 62%∼92% were investigated. Optical observations found that the cell struts and ligaments consist of primary α' martensite. These cellular structures have comparable compressive strength (4∼113 MPa) and elastic modulus (0.2∼6.3 GPa) to those of trabecular and cortical bone. The regular mesh structures exhibit higher specific strength than other reported metallic foams under the condition of identical specific stiffness. During the compression, these EBM samples have a brittle response and undergo catastrophic failure after forming crush band at their peak loading. These bands have identical angle of ∼45° with compression axis for the regular reticulated meshes and such failure phenomenon was explained by considering the cell structure. Relative strength and density follow a linear relation as described by the well-known Gibson-Ashby model but its exponential factor is ∼2.2, which is relative higher than the idea value of 1.5 derived from the model.
TL;DR: Standardization on Shear wave ultrasound elastography technical settings will not only ensure that the results are accurate, but also detect any differences over time that may be attributed to true physiological changes.
Abstract: Standardization on Shear wave ultrasound elastography (SWUE) technical settings will not only ensure that the results are accurate, but also detect any differences over time that may be attributed to true physiological changes. The present study evaluated the variations of elastic modulus of muscle and tendon using SWUE when different technical aspects were altered. The results of this study indicated that variations of elastic modulus of muscle and tendon were found when different transducer’s pressure and region of interest (ROI)’s size were applied. No significant differences in elastic modulus of the rectus femoris muscle and patellar tendon were found with different acquisition times of the SWUE sonogram. The SWUE on the muscle and tendon should be performed with the lightest transducer’s pressure, a shorter acquisition time for the SWUE sonogram, while measuring the mean elastic modulus regardless the ROI’s size.
TL;DR: In this paper, the room temperature elastic moduli (Young's modulus, shear modulus and bulk modulus) and hardness were measured by resonant ultrasound spectroscopy, and Vickers indentation, respectively.
Abstract: Cubic garnet Li6.24La3Zr2Al0.24O11.98 (LLZO) is a candidate material for use as an electrolyte in Li–Air and Li–S batteries. The use of LLZO in practical devices will require LLZO to have good mechanical integrity in terms of scratch resistance (hardness) and an adequate stiffness (elastic modulus). In this paper, the powders were fabricated by powder processing of cast ingots. All specimens were then densified via hot pressing. The room temperature elastic moduli (Young’s modulus, shear modulus, bulk modulus, and Poisson’s ratio) and hardness were measured by resonant ultrasound spectroscopy, and Vickers indentation, respectively. For volume fraction porosity, P, the Young’s modulus was 149.8 ± 0.4 GPa (P = 0.03) and 132.6 ± 0.2 GPa (P = 0.06). The mean Vickers hardness was 6.3 ± 0.3 GPa for P = 0.03 and 5.2 ± 0.4 for P = 0.06.
TL;DR: In this paper, the authors present an experimental study on the behavior of CFRP-to-steel bonded interfaces through the testing of a series of single-lap bonded joints and demonstrate that the bond strength of such bonded joints depends strongly on the interfacial fracture energy among other factors.
Abstract: This paper presents an experimental study on the behaviour of CFRP-to-steel bonded interfaces through the testing of a series of single-lap bonded joints. The parameters examined include the material properties and the thickness of the adhesive layer and the axial rigidity of the CFRP plate. The test results demonstrate that the bond strength of such bonded joints depends strongly on the interfacial fracture energy among other factors. Nonlinear adhesives with a lower elastic modulus but a larger strain capacity are shown to possess a much higher interfacial fracture energy than linear adhesives with a similar or even a higher tensile strength. The variation of the interfacial shear stress distribution in a bonded joint as the applied load increases clearly illustrates the existence of an effective bond length. The bond–slip curve is shown to have an approximately triangular shape for a linear adhesive but to have an approximately trapezoidal shape for a nonlinear adhesive, indicating the necessity of developing different forms of bond–slip models for different adhesives.
TL;DR: In this paper, a linear-elastic model incorporating an out-of-plane restoring force due to solid surface tension was recently shown to accurately predict the equilibrium shape of a thin elastic film due to a large sessile droplet.
Abstract: Young's law fails on soft solid and liquid substrates where there are substantial deformations near the contact line. On liquid substrates, this is captured by Neumann's classic analysis, which provides a geometrical construction for minimising the interfacial free energy. On soft solids, the total free energy includes an additional contribution from elasticity. A linear-elastic model incorporating an out-of-plane restoring force due to solid surface tension was recently shown to accurately predict the equilibrium shape of a thin elastic film due to a large sessile droplet. Here, we extend this model to find substrate deformations due to droplets of arbitrary size. While the macroscopic contact angle matches Young's law for large droplets, it matches Neumann's prediction for small droplets. The cross-over droplet size is roughly given by the ratio of the solid's surface tension and elastic modulus. On thin substrates at this cross-over, the macroscopic contact angle increases, indicating that the substrate is effectively less wetting. For droplets of all sizes, the microscopic behaviour near the contact line follows the Neumann construction giving local force balance.
TL;DR: In this article, the effect of temperature on peak stress, elastic modulus, and peak strain of heated granite is investigated and a linear relationship between the damage parameter and fatigue life is found.
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08 Dec 2012
TL;DR: In this paper, the authors proposed a transformation field analysis (TFA) of inelastic deformation of elastic moduli of fibrous composites, including inclusions, inhomogeneities, dilute reinforcements and cracks.
Abstract: 1 Tensor component and matrix notation- 2 Anisotropic elastic solids- 21 Elastic strain energy density- 22 Material symmetries- 23 Transversely isotropic composite materials- 24 Cylindrically orthotropic materials- 25 Young's modulus, shear modulus and Poisson's ratio- 3 Elementary concepts and tools- 31 Aggregates and constituent phases- 32 Herogeneous microstructures- 33 Representative volume- 34 Local and overall stress and strain fields- 35 Overall properties and local fields- 36 Transformation fields- 37 Work, energy and reciprocal theorems- 38 The Levin formula and the Hill lemma- 39 Universal connections for elastic moduli of fibrous composites- 310 Constitutive relations and local fields in heterogeneous aggregates- 4 Inclusions, inhomogeneities and cavities- 41 Homogeneous ellipsoidal inclusions: The Eshelby solution- 42 Ellipsoidal inhomogeneities: The equivalent inclusion method- 43 Transformed inhomogeneities- 44 Dilute approximation of overall properties- 45 Green's function and Eshelby's tensor in elastic solids- 46 Coefficients of the P tensors for selected ellipsoidal shapes- 47 Summary of principal results- 5 Energies of inhomogeneities, dilute reinforcements and cracks- 51 Energy changes caused by mechanical loads- 52 Energy changes caused by uniform phase eigenstrains- 53 Energy changes caused by mechanical loads and phase eigenstrains- 54 Energy and stiffness changes caused by cracks- 6 Evaluations and bounds on elastic moduli of heterogeneous materials- 61 Elementary energy bounds- 62 Hashin-Shtrikman and Walpole bounds on overall elastic moduli- 63 Evaluation of H-S bounds for ellipsoidal inhomogeneities- 64 Composite element assemblage bounds- 65 The generalized self-consistent method- 7 Estimates of mechanical properties of composite materials- 71 The self-consistent method (SCM)- 72 The Mori-Tanaka method (M-T)- 73 The differential scheme- 74 The double inclusion and double inhomogeneity models- 75 Applications of SCM and M-T to functionally graded materials- 8 Transformation fields- 81 Uniform change of temperature in two-phase composites and polycrystals- 82 Transformation influence functions and concentration factors- 83 Uniform change in temperature in multiphase systems- 84 Capabilities of bounds and estimates of overall and local fields- 9 Interfaces and interphases- 91 Perfectly bonded interfaces- 92 Imperfectly bonded inhomogeneities and cavities- 10 Symmetric laminates- 101 Constitutive relations of fibrous plies- 102 Coordinate systems and transformations- 103 Overall response and ply stresses in symmetric laminates- 104 Ply and constituent stress and strain averages - 105 Design of laminates for cylindrical pressure vessels- 106 Dimensionally stable laminates- 107 Auxetic laminates- 108 Laminates with reduced free edge stresses- 11 Elastic-plastic solids- 111 Yield and loading surfaces, normality and convex- 112 Hardening and flow rules- 113 Matrix form and consistency of the instantaneous tangent stiffness- 12 Inelastic composite materials- 121 Transformation field analysis (TFA) of inelastic deformation- 122 Experimental support of theoretical predictions- 123 Thermal hardening- References
TL;DR: A highly accurate method to determine Gaussian curvature modulus κ¯ in computer simulations relies on the interplay between curvature stress and edge tension of partially curved axisymmetric membrane disks and requires determining their closing probability.
TL;DR: Analysis of the response of single 3T3 fibroblasts that were indented with a micrometer-sized bead attached to an AFM cantilever at forces from 30–600 pN found that at such small deformations, the elastic modulus of 100 Pa is largely determined by the presence of the actin cortex.
Abstract: The measurement of the elastic properties of cells is widely used as an indicator for cellular changes during differentiation, upon drug treatment, or resulting from the interaction with the supporting matrix. Elasticity is routinely quantified by indenting the cell with a probe of an AFM while applying nano-Newton forces. Because the resulting deformations are in the micrometer range, the measurements will be affected by the finite thickness of the cell, viscous effects and even cell damage induced by the experiment itself. Here, we have analyzed the response of single 3T3 fibroblasts that were indented with a micrometer-sized bead attached to an AFM cantilever at forces from 30-600 pN, resulting in indentations ranging from 0.2 to 1.2 micrometer. To investigate the cellular response at lower forces up to 10 pN, we developed an optical trap to indent the cell in vertical direction, normal to the plane of the coverslip. Deformations of up to two hundred nanometers achieved at forces of up to 30 pN showed a reversible, thus truly elastic response that was independent on the rate of deformation. We found that at such small deformations, the elastic modulus of 100 Pa is largely determined by the presence of the actin cortex. At higher indentations, viscous effects led to an increase of the apparent elastic modulus. This viscous contribution that followed a weak power law, increased at larger cell indentations. Both AFM and optical trapping indentation experiments give consistent results for the cell elasticity. Optical trapping has the benefit of a lower force noise, which allows a more accurate determination of the absolute indentation. The combination of both techniques allows the investigation of single cells at small and large indentations and enables the separation of their viscous and elastic components.
TL;DR: High-resolution topographic and quantitative mechanics data of phase-separated SLBs are acquired using a recent atomic force microscopy (AFM) imaging mode based on force measurements to evaluate the contribution of the underlying hard support in the determination of the elastic properties of SLBs and to determine the adequate indentation range for obtaining reliable elastic moduli values.
TL;DR: In this paper, a finite element model for 3D random fiber networks was constructed to simulate deformation and failure behavior of networks with dynamic bonding/debonding properties, and a key feature of this new network model is the fiber-fiber interaction model that is based on AFM measurements from their earlier study.
TL;DR: In this article, the authors describe a micromechanical analysis of the uniaxial response of composites comprising elastic platelets (bricks) bonded together with thin elastic perfectly plastic layers (mortar).
Abstract: This paper describes a micromechanical analysis of the uniaxial response of composites comprising elastic platelets (bricks) bonded together with thin elastic perfectly plastic layers (mortar). The model yields closed-form results for the spatial variation of displacements in the bricks as a function of constituent properties, which can be used to calculate the effective properties of the composite, including elastic modulus, strength and work-to-failure. Regime maps are presented which indicate critical stresses for failure of the bricks and mortar as a function of constituent properties and brick architecture. The solution illustrates trade-offs between elastic modulus, strength and dissipated work that are a result of transitions between various failure mechanisms associated with brick rupture and rupture of the interfaces. Detailed scaling relationships are presented with the goal of providing material developers with a straightforward means to identify synthesis targets that balance competing mechanical behaviors and optimize material response. Ashby maps are presented to compare potential brick and mortar composites with existing materials, and identify future directions for material development.
TL;DR: In this paper, the effect of the stress required to close an initially open crack, and the unloading process in detail, is examined. But the model does not seem to have previously been developed in sufficient detail to be used for quantitative predictions.
TL;DR: A systematic comparative study of the stability, structural and mechanical properties of graphynes - a variation of the sp(2) carbon motif wherein the characteristic hexagons of graphene are linked by sp(1) acetylene (single- and triple-bond) carbyne-like chains, suggesting applications for light-weight, yet structurally robust molecular components.
Abstract: The mono-atomistic structure and chemical stability of graphene provides a promising platform to design a host of novel graphene-like materials. Using full atomistic first-principles based ReaxFF molecular dynamics, here we perform a systematic comparative study of the stability, structural and mechanical properties of graphynes – a variation of the sp2 carbon motif wherein the characteristic hexagons of graphene are linked by sp1 acetylene (single- and triple-bond) carbyne-like chains. The introduction of acetylene links introduces an effective penalty in terms of stability, elastic modulus (i.e., stiffness), and failure strength, which can be predicted as a function of acetylene repeats, or, equivalently, lattice spacing. We quantify the mechanical properties of experimental accessible graphdiyne, with a modulus on the order of 470 to 580 GPa and a ultimate strength on the order of 36 GPa to 46 GPa (direction dependent). We derive general scaling laws for the cumulative effects of additional acetylene repeats, formulated through a simple discrete spring-network framework, allowing extrapolation of mechanical performance to highly extended graphyne structures. Onset of local tensile buckling results in a transitional regime characterized by a severe reduction of strength (ultimate stress), providing a new basis for scaling extended structures. Simple fracture simulations support the scaling functions, while uncovering a “two-tier” failure mode for extended graphynes, wherein structural realignment facilitates stress transfer beyond initial failure. Finally, the specific modulus and strength (normalized by areal density) is found to be near-constant, suggesting applications for light-weight, yet structurally robust molecular components.
TL;DR: MoS2 sheets show high elasticity and an extremely high Young's modulus, which make them a potential alternative to graphene in applications requiring flexible semiconductor materials.
Abstract: We fabricate freely suspended nanosheets of molybdenum disulphide (MoS2) which are characterized by quantitative optical microscopy and high-resolution friction force microscopy We study the elastic deformation of freely suspended nanosheets of MoS2 using an atomic force microscope The Young’s modulus and the initial pretension of the nanosheets are determined by performing a nanoscopic version of a bending test experiment MoS2 sheets show high elasticity and an extremely high Young’s modulus (030 TPa, 50% larger than steel) These results make them a potential alternative to graphene in applications requiring flexible semiconductor materials PACS, 7361Le, other inorganic semiconductors, 6865Ac, multilayers, 6220de, elastic moduli, 8140Jj, elasticity and anelasticity, stress-strain relations
TL;DR: In this article, the effects of particle softness and the role of the outer shell mechanics on the linear viscoelasticity and yielding behaviour of colloidal glasses are critically assessed using three different model colloidal particles: (i) sterically stabilized PMMA particles with model hard sphere interactions, (ii) core-shell microgels with a deformable PNIPAM outer shell and (iii) ultra-soft star-like micelles with interpenetrable multi-arms.
Abstract: The effects of particle softness and the role of the outer shell mechanics on the linear viscoelasticity and yielding behaviour of colloidal glasses are critically assessed using three different model colloidal particles: (i) sterically stabilized PMMA particles with model hard sphere interactions, (ii) core–shell microgels with a deformable PNIPAM outer shell and (iii) ultra-soft star-like micelles with inter-penetrable multi-arms. The volume fraction dependence of the elastic modulus and the yield stress reflects the softness of the effective inter-particle potential. The yield strain exhibits distinct non-monotonic volume fraction dependence for hard spheres below close packing whereas for both soft particles it increases above close packing due to particle softness. Stress overshoots in start-up shear show a common increase with shear rate in all systems. However, the stress overshoots are significantly stronger in star-like micelles due to transient arm entanglements. In relation with that similar stress peaks are detected within the period of the large amplitude oscillatory shear only in star-like micelles. Finally, we discuss the scaling exponents for the G′ and G′′ decrease at large oscillatory strain amplitudes and their relation with steady shear stress.
TL;DR: In this paper, the effect of polymer-graft modification on the structure formation and mechanical characteristics of inorganic (silica) nanoparticle solids is evaluated as a function of the degree of polymerization of surface-grafted chains.
Abstract: The effect of polymer-graft modification on the structure formation and mechanical characteristics of inorganic (silica) nanoparticle solids is evaluated as a function of the degree of polymerization of surface-grafted chains. A transition from ‘hard-sphere-like’ to ‘polymer-like’ mechanical characteristics of particle solids is observed for increasing degree of polymerization of grafted chains. The elastic modulus of particle solids increases by about 200% and levels off at intermediate molecular weights of surface-grafted chains, a trend that is rationalized as a consequence of the elastic modulus being determined by dispersion interactions between the polymeric grafts. A pronounced increase (of about one order of magnitude) of the fracture toughness of particle solids is observed as the degree of polymerization of grafted chains exceeds a threshold value that is similar for both polystyrene and poly(methyl methacrylate) grafts. The increased resistance to fracture is interpreted as a consequence of the existence of entanglements between surface-grafted chains that give rise to energy dissipation during fracture through microscopic plastic deformation and craze formation. Within the experimental uncertainty the transition to polymer-like deformation characteristics is captured by a mean field scaling model that interprets the structure of the polymer shell of polymer-grafted particles as effective ‘two-phase’ systems consisting of a stretched inner region and a relaxed outer region. The model is applied to predict the minimum degree of polymerization needed to induce polymer-like mechanical characteristics and thus to establish ‘design criteria’ for the synthesis of polymer-modified particles that are capable of forming mechanically robust and formable particle solid structures.
TL;DR: In this article, a surface of epoxy-impregnated hardened cement paste was investigated using a novel atomic force microscopy (AFM) imaging mode that allows for the quantitative mapping of the local elastic modulus.
TL;DR: The microstructure and mechanical properties of nano composites processed via stir casting were studied in this article, where the composites were based on the A356 aluminum alloy reinforced with nano SiC particles.