Liquid marble: A novel liquid nanofoam structure for energy absorption

Mingzhe Li,Weiyi Lu

doi:10.1063/1.4984231

Abstract

The liquid nanofoam (LN), a system composed of liquid and hydrophobic nanoporous particles, is a promising energy absorbing material. Despite its excellent energy absorbing capabilities under quasi-static conditions, the LN’s performance is limited under dynamic impacts due to its heterogeneity. We hypothesize that the energy absorption capacity of the LN can be increased by reconfiguration of the material into a liquid marble form. To test this hypothesis, we have prepared the LN sample in two different configurations, one with the heterogeneous layered structure and the other with a macroscopically homogeneous liquid marble structure. The mechanical behavior of these two types of LN was examined by quasi-static compression tests and dynamic impact tests. We demonstrated that although both types of LN exhibited comparable quasi-static energy absorption capacity, the liquid marble form of LN showed better performance under dynamic impacts. These findings suggest that the liquid marble form is the preferred LN structure under blunt impact and shed lights on the design of next-generation energy absorbing materials and structures.

Highlights

The increasing interest in the protection of personnel and civil infrastructures from impact has led to extensive researches on the design of advanced energy absorbing materials and structures
The specific volume change of the liquid nanofoam (LN) (0.2 cm3/g) at 0.9 MPa is the elastic compression of the liquid phase and the nanoporous particles
In contrast to the reduction in energy absorption capacity of the LN-L sample, the dynamic behavior of LN-M is strain rate insensitive (Fig. 3b). Both the total deformability as well as the liquid infiltration pressure range remain the same as measured in the quasi-static compression test. These results suggest that the LN-M sample is more efficient than the LN-L sample at increased strain rates, and the energy absorption capacity of the LN is fully activated in its liquid marble form

Summary

INTRODUCTION

The increasing interest in the protection of personnel and civil infrastructures from impact has led to extensive researches on the design of advanced energy absorbing materials and structures. A liquid nanofoam (LN) system with high energy absorption efficiency was developed for high-performance protection devices.[12,13,14,15,16,17] The LN system is composed of liquid and hydrophobic nanoporous materials, the latter containing large volume fraction of nanometer pores whose surface is specially treated and non-wettable to the liquid phase.[17] When an external impact is sufficiently high, the surface energy barrier is overcome and the liquid molecules are forced into the nanopores During this liquid infiltration process, large amount of external energy is converted into solid-liquid interfacial tension and dissipated as heat.[18] For a single nanopore, it has been demonstrated that the LN system possesses both high energy absorption efficiency and ultra-fast energy dissipation rate.[15,19]. Reconfiguration of LN into the liquid marble form offers a promising approach for the protection from blunt impact and the design of next-generation energy absorbers

EXPERIMENTAL

RESULTS AND DISCUSSIONS

SUMMARY