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Slippery liquid-infused porous surfaces are vulnerable to lubricant depletion caused by three major factors encompassing, the evaporation, cloaking, and shearing. Herein, lubricant-infused iron palmitate surfaces (LI-IPSs) are presented addressing the challenges of (1) evaporation-driven lubricant depletion enabled by the immensely clustered micro-/nano-structures of iron palmitate surface (IPS), (2) completely suppressing the wetting ridge even with miscible water-oil combinations enabled by only the handful uptake of oil by IPS. The apparent contact angle θa and sliding angle α of water on LI-IPSs are 98° ± 2° and 3° ± 1°, respectively. Under evaporation-driven lubricant depletion analysis, the shelf-durability of LI-IPSs has been found to last for 10 days in partially open environment at the ambient temperature (25 °C). The heat fluxes and condensate fluxes have been determined. The highest condensate flux on LI-IPSs (14 kgh−1 m−2) is ascribed to the dropwise condensation mode with efficient droplet dynamics. However, the service durability of LI-IPSs has lasted only for 50 ± 5 min under rigorous condensation, which is further addressed by developing a LI-IPS prototype. Based on the excellent wicking capability of IPS, LI-IPS prototype is capable of maintaining the dropwise condensation unless the oil is available in the oil tub. The LI-IPS prototype has been subjected to open environment at ambient temperature for 168 h, and even after that, the stable dropwise condensation has been achieved with the same range of droplet speed as had been observed in the first hour. Meantime, the high condensation heat fluxes at various subcooling temperatures are obtained, justifying the promising ability of LI-IPS. [ABSTRACT FROM AUTHOR]

Since its emergence, the pseudopotential lattice Boltzmann (LB) method has been regarded as a straightforward and practical approach for simulating single-component multiphase flows. However, its original form always results in a thermodynamic inconsistency, which, thus, impedes its further application. Several strategies for modifying the force term have been proposed to eliminate this limitation. In this study, four typical and widely used improved schemes—Li's single-relaxation-time (SRT) scheme [Li et al., "Forcing scheme in pseudopotential lattice Boltzmann model for multiphase flows," Phys. Rev. E 86, 016709 (2012)] and multiple-relaxation-times (MRT) scheme [Li et al., "Lattice Boltzmann modeling of multiphase flows at large density ratio with an improved pseudopotential model," Phys. Rev. E 87, 053301 (2013)], Kupershtokh's SRT scheme [Kupershtokh et al., "On equations of state in a lattice Boltzmann method," Comput. Math. Appl. 58, 965 (2009)], and Huang's MRT scheme [Huang and Wu, "Third-order analysis of pseudopotential lattice Boltzmann model for multiphase flow," J. Comput. Phys. 327, 121 (2016)]—are systematically analyzed and intuitively compared after an extension of the MRT framework. The theoretical and numerical results both indicate that the former three schemes are specific forms of the last one, which thus help further understand the improvements of these pseudopotential LB models for achieving thermodynamic consistency. In addition, we modified the calculation of the additional source term in the LB evolution equation. Numerical results for stationary and moving droplets confirm the higher accuracy. [ABSTRACT FROM AUTHOR]

This paper describes a numerical investigation of the groove-embedded droplet dewetting process, namely the spontaneous transition from the Wenzel state to the Cassie state, using the multiphase lattice Boltzmann method. Numerical simulations are employed to reproduce the dynamic behaviors of extension, squeezing, rupture, and ejection of condensation droplets in a groove, allowing us to examine how the groove geometry and wettability affect the dewetting process. Our results identify three dewetting regimes, namely retention, partial dewetting, and complete dewetting. As the groove aspect ratio and hydrophilicity decrease, the dewetting regime changes from retention to partial dewetting, and then to complete dewetting. The partial dewetting and complete dewetting are two effective ways for droplet removing. In particular, a groove sidewall with enhanced hydrophobicity is desirable to stimulate the dewetting process. [ABSTRACT FROM AUTHOR]

Bioinspired self-healing carriers can cost-effectively repair crack damage in functional materials without detection, analysis, or any type of human intervention. In this study, an effective structured self-healing microcarrier is prepared through a single-step microfluidic method. These microcarriers are self-contained core-shell microcapsules with the healant and the curing agent encapsulated in separate chambers of a single capsule. Because microfluidics are versatile, our fabrication method generates unique structures in which the ratio of the agents can be precisely adjusted, and thus, the reaction kinetics and the cost can be well controlled. Such carriers can be embedded into various material matrices, including bulk pellets and film materials, which maintain satisfactory mechanical properties after being damaged and repaired. These attractive features may establish an approach for microfluidic preparation of self-healing materials and may open up avenues for the development of intelligent self-healing materials for military equipment, electronic products, architectural materials, etc. [ABSTRACT FROM AUTHOR]

A molecular dynamics simulation of slip boundary for fluid flow past a solid surface incorporating roughness effect as characterized by fractal geometry has been conducted with a focus on the origin of slip, fluid structure, and slip boundary flow. The results indicate that interfacial slip develops provided that the wall is effectively uncorrugated. Compared with the atomically smooth surface, extra viscous dissipation is induced for shear flow past a rough surface and leading to a reduction in boundary slip. In particular, we find that a more irregular topography decreases the boundary slip even for the same statistical roughness height. [ABSTRACT FROM AUTHOR]