To predict the properties of superamphiphobic layers we analyzed wetting a square and hexagonal array vertical pillars composed spheres (radius R) partially sintered together. Apparent contact angles above 150° are obtained by pinning non-polar liquid surface at underside top sphere resulting in Fakir or Cassie state. Analytical equations derived for impalement pressure limiting case A0 ≫ R2, where is area regular unit cell containing single pillar. The close investigated numerically. By...

Static and dynamic elastic moduli of Calcare Massiccio mudstone-limestone, the typical seismogenic rock in Italian Apennines, are measured using a standard uniaxial static compression test, dual cantilever forced oscillation test ultrasonic measurement wave velocities. These measurements cover nine decades frequency including seismic domain. Neither significant dependence nor pronounced strain amplitude was observed, providing Young's modulus (75 ± 7) GPa Poisson's ratio (0.28 0.02). values...

The present review is intended to revisit the advances and debates in comprehension of mechanisms subcritical crack propagation silicate glasses almost a century after its initial developments. Glass has inspired insights Griffith into origin brittleness ensuing development modern fracture mechanics. Yet, through decades real nature fundamental glass escaped clear which could gather general agreement on subtle problems such as role plasticity, composition, environmental condition at tip...

Tough elastomers that resist fracture at high loads are not optimum for sustaining many cycles low loads.

We investigate experimentally the adherence energy Γ of model polyacrylate pressure-sensitive adhesives (PSAs) with combined large strain rheological measurements in uniaxial extension and an instrumented peel test. develop a nonlinear for such test which captures dependence Γ(V) peeling rate V, revealing key role played by extensional rheology. Our explains particular why traditional linear viscoelastic approaches correctly predict slope curves sufficiently elastic PSAs characterized simple...

Thermoplastic polyurethane elastomers (TPU) are stretchable, tough, wear resistant and easily processable soft materials. Especially because of their recyclability, TPUs can be suitable candidates to replace rubbers in several applications such as damping, footwear cable coatings. However, capacity operate under cyclic loads over many cycles was rarely investigated, mainly due complex strain-dependent morphology viscoplastic character. Additionally, the absence chemical crosslinks results a...

Atomic Force Microscope images of a crack intersecting the free surface glass specimen are taken at different stages subcritical propagation. From analysis image pairs, it is shown that novel Integrated Digital Image Correlation technique allows to measure stress intensity factors in quantitative fashion. sizes as small 200 nm can be exploited and displacement fields do not show significant deviations from linear elastic solutions down 10 distance tip. Moreover, this gives access out-of-plane

The modelling of the adherence energy during peeling Pressure Sensitive Adhesives (PSA) has received much attention since 1950's, uncovering several factors that aim at explaining their high on most substrates, such as softness and strong viscoelastic behaviour adhesive, low thickness adhesive layer its confinement by a rigid backing. more recent investigation adhesives probe-tack methods also revealed importance cavitation stringing mechanisms debonding, underlining influence large...

The performances of Pressure Sensitive Adhesives (PSA) are generally evaluated using different loading geometries such as tack, peel and shear tests. It is difficult to link the behaviors PSAs in these geometries, predict result one test from another, because confinement a soft dissipative material prevents use standard fracture mechanics, which separates interface debonding behavior dissipation associated with bulk deformation. We present here an original experimental investigation based on...

When Griffith presented his famous theory of crack stability in elastic materials the early twentieth century, he was unable to provide much detail on structure cracks at nanometer level resolution. Now, almost 100 years later, techniques such as transmission electron microscopy, atomic force microscope, nuclear reaction analysis, and reflection are available achieve this Here, we review kind data obtained using these implications vis‐á‐vis silicate glasses. Measurements by microscopy...

The fracture of materials can take place below the critical failure condition via slow accumulation internal damage followed by fast crack propagation. While due to subcritical accounts for most structural failures in use, it is theoretically challenging bridge gap between molecular and mechanics, not mention predicting occurrence sudden fracture, lack current nondestructive detection methods with suitable resolution. Here, we investigate elastomers using simultaneously space- time-resolved...

Abstract This work investigates the correlation between formulation of waterborne acrylic pressure‐sensitive adhesives (PSAs) and their resulting adhesive performance. A library n ‐butyl acrylate‐based latexes is synthesized via miniemulsion polymerization. Controlled variations in composition these polyacrylates – such as inclusion rigid comonomers, latent crosslinkers chain transfer agents enabled precise control over key network structures particles leading then to a range physical...

In stick-slip fracture, a crack stays still or only propagates small amount until it reaches critical energy release rate. Then, suddenly grows rapidly, causing the release...

The roughness of fracture surfaces exhibits self-affinity for a wide variety materials and loading conditions. universality the range scales over which this regime extends are still debated. topography these is however often investigated with finite contact probe. In case, we show that correlation function can only be measured down to length scale $\ensuremath{\Delta}{x}_{c}$ depends on probe size $R$, Hurst exponent $\ensuremath{\zeta}$ surface its topothesy $l$, spurious behavior at...

We extend to the case of perfect wetting exact calculation Orr et al. (J. Fluid. Mech. 1975, 67, 723) for a pendular ring connecting two dry surfaces. derive an approximate analytical expression capillary force between highly curved surfaces covered by liquid film. The domain validity this is assessed and extended custom-made numerical simulation based on full mathematical description. In attractive liquid-solid van der Waals interactions, increases monotonically with decreasing vapor...

During pendant drop experiments, a model physical gel made from oil in water microemulsion droplets reversibly linked together by triblock copolymers, exhibit very peculiar filament rupture corresponding to highly brittle failure of viscoelastic fluid. The fracture propagation has been tracked high speed videomicroscopy. Analysis the time evolution profile shows that is purely elastic and reversible without any significant bulk interfacial viscous dissipation. However, since moduli such...

We use photon correlation imaging, a recently introduced space-resolved dynamic light scattering method, to investigate the spatial of dynamics variety jammed and glassy soft materials. Strikingly, we find that in deeply materials correlations are quite generally ultra-long ranged, extending up system size, orders magnitude larger than any relevant structural length scale, such as particle or mesh size for colloidal gel systems. This has be contrasted with case molecular, granular...

For decades, polyvinylbutyral (PVB) has been the polymer of choice to improve impact resistance laminated glass. PVB presents large rupture strain, tensile strength, and excellent dissipative properties. Here, we investigate relation between macromolecular structure mechanical properties plasticized by combining strain experiments with calorimetry, X-ray, birefringence measurements. We find that response is dominated creep this plastic-like flow can effectively be described a...

Despite their technological relevance, the resistance of soft thermoplastic polyurethanes (TPU) to crack propagation in cyclic fatigue has never been investigated detail. In particular, a clear shortcoming literature for this class materials is lack connection between and large strain behavior that fundamental role defining material's propagation. We demonstrate here first time when strain-induced stiffening mechanism TPU (already observed deformation) combined with presence nonhomogeneous...