Superhydrophobic surfaces have important technical applications ranging from self-cleaning window glasses, paints, and fabrics to low-friction surfaces. The archetype superhydrophobic surface is that of the lotus leaf. When rain falls on leaves, water beads up with a contact angle in range about 160°. drops promptly roll off leaves collecting dirt along way. This effect has, recent years, stimulated much research effort worldwide fabrication superhydrophobicity. But, truly superhydrophobic?...

The work done during indentation is examined using dimensional analysis and finite element calculations for conical in elastic-plastic solids with hardening. An approximate relationship between the ratio of hardness to elastic modulus irreversible total found. Consequently, may be obtained directly from measuring indentation. Together a well-known modulus, initial unloading slope, contact area, new method then suggested estimating instrumented or pyramidal indenters.

When rain falls on lotus leaves water beads up with a high contact angle. The drops promptly roll off the leaves, collecting dirt along way. This self-cleaning ability or effect has, in recent years, stimulated much research effort worldwide for variety of applications ranging from window glasses, paints, and fabrics to low friction surfaces. What are mechanisms giving rise effect? Although chemical composition surface structure believed important, systematic experimental investigation their...

The solid electrolyte interphase (SEI), a passivation layer formed on electrodes, is critical to battery performance and durability. inorganic components in SEI, including lithium carbonate (Li2CO3) fluoride (LiF), provide both mechanical chemical protection, meanwhile control ion transport. Although Li2CO3 LiF have relatively low ionic conductivity, we found, surprisingly, that the contact between can promote space charge accumulation along their interfaces, which generates higher carrier...

Coupled mechanical-chemical degradation of electrodes upon charging and discharging has been recognized as a major failure mechanism in lithium ion batteries. The instability commonly employed electrolytes results solid electrolyte interphase (SEI) formation. Although the SEI layer is necessary, it passivates electrode-electrolyte interface from further solvent decomposition, formation consumes thus contributes to irreversible capacity loss. In this paper, we study loss graphite-LiFePO4...

We examine the effects of surface tension and modulus on diffusion-induced stresses within spherical nanoparticles. show that both magnitude distribution can be significantly affected by mechanics if particle diameter is in nanometer range. In particular, a tensile state stress may reduced or even reverted to compressive with decreasing radius. This reduction responsible for observed resilience fracture decrepitation nanoparticles used various industrial applications.

Cracking of electrodes caused by large volume change and the associated lithium diffusion-induced stress during electrochemical cycling is one main reasons for short cycle life lithium-ion batteries using high capacity anode materials, such as Si Sn. In this work, we study fracture behavior cracking patterns in amorphous thin film a result cycling. A modified spring-block model shown to capture essential features electrode including self-similarity. It that cracks are straight thick films,...

For advancing lithium-ion battery (LIB) technologies, a detailed understanding of degradation mechanisms is important. In this article, experimental observations are provided to elucidate the relation between side reactions, mechanical degradation, and capacity loss in LIBs. Graphite/Li(Ni1/3Mn1/3Co1/3)O2 cells two very different initial anode/cathode ratios (R, both R > 1) assembled investigate electrochemical behavior. The charge cathode observed be affected by anode loading, indicating...

The crucial role of mechanical stress in voltage hysteresis lithium ion batteries charge–discharge cycles is investigated theoretically and experimentally.

We derive, using dimensional analysis and finite element calculations, several scaling relationships for conical indentation in elastic-plastic solids with work hardening. Using these relationships, we examine the between hardness, contact area, initial unloading slope, mechanical properties of solids. The also provide new insights into shape curves form basis understanding measurements, including nano- micro-indentation techniques. They may be helpful as a guide to numerical calculations problems.

Bilayer polymers that consist of two epoxy dual-shape memory well-separated glass transition temperatures have been synthesized. These bilayer samples exhibit a triple-shape effect (TSME) with shape fixities tailorable by changing the ratio between layers. The can be explained balance stress Based on this work, it is believed following three molecular design criterions should considered in designing optimum TSME: 1) thermal transitions, 2) strong interface, and 3) an appropriate moduli...

Most lithium-ion battery electrodes experience large volume changes caused by concentration within the host particles during charging and discharging. Electrode failure, in form of fracture or decrepitation, can occur as a result repeated changes. In this work, we first develop analytic solutions for evolution stresses spherical electrode element under charging–discharging conditions when system thermodynamics are ideal (e.g., no repulsion forces significant between intercalate species)....

Abstract Using dimensional analysis and finite-element calculations, several relationships that relate features of indentation loading unloading curves to the hardness, elastic modulus work are extended conical in elastic-plastic solids with various angles. These provide new insights into measurements. They may also be useful interpretation results obtained from instrumented experiments.

A multicomposite shape memory polymer (SMP) with remote and selective triggering of the recovery multiple temporary shapes in radiofrequency fields is demonstrated. Each deformed region can be independently actuated at a specific frequency based on filler type region. In addition, nanocomposite SMP exhibits possible routes.

We present a study of the effects ratio hardness to Young’s modulus on friction and wear behavior layered composite coatings. Layered coating structures with same surface but different interlayers were prepared by physical vapor deposition. found that plays an important role in determining coefficient resistance A low high can be achieved moderately hardness.

The effective interdiffusion coefficient of metallic bilayers under ion irradiation has been correlated with the heat mixing corresponding binary alloys. results are interpreted according to Darken’s theory chemically enhanced diffusion.

Understanding the ionic conduction in solid electrolytes contact with electrodes is vitally important to many applications, such as lithium ion batteries. The problem complex because both internal properties of materials (e.g., electronic structure) and characteristics externally contacting phases voltage electrode) affect defect formation transport. In this paper, we developed a method based on density functional theory study physics defects electrolyte equilibrium an external environment....