Yueting Sun

Mechanical Energy Absorption Characteristics of Hollow and Water-Filled Carbon Nanotubes upon Low-Speed Crushing

AbstractUsing molecular dynamics simulations, the prospects are explored of using bundles, forests, and single carbon nanotubes (CNTs) for absorbing mechanical energies upon crushing. In particular, the deformation and energy absorption characteristics are compared between hollow and water-filled CNTs. It is shown that the buckling properties of hollow CNTs strongly depend on their geometrical parameters, whereas the critical buckling load and postbuckling stress can be significantly elevated with a filament of water, leading to pronounced energy absorption densities. Additional enhancements result from CNT bundles and forests. The present study may provide some insight into the potential application of employing CNTs as advanced energy absorption materials.

Mechanism of water infiltration and defiltration through ZSM-5 zeolite: heating and sodium chloride concentration effect

Hydrophobic nanoporous material and wetting liquid together comprise a system with promising energy related applications. The mechanism of the interaction between liquid and solid phase is not fully explored. In this paper, based on the quasistatic compression experiments on investigating the mechanical behavior of ZSM-5 zeolite/NaCl solution system, the effects of two key parameters, that is, the pretreatment temperature of ZSM-5 zeolite and NaCl concentration, are parametrically and quantitatively investigated based on Laplace-Washburn equation. Results show that both pretreatment temperature and NaCl concentration raise the infiltration pressure and NaCl can also promote defiltration. The advancing contact and receding contact angle of zeolite-NaCl-air system increase with both pretreatment temperature and NaCl concentration, and the contact angle hysteresis decreases with NaCl concentration. Results may provide fundamental explanation to the nanoconfined liquid behavior and liquid-solid interaction, thus, to smartly control the mechanical properties of the liquid spring and bumpers for energy dissipation function.

Intrusion of polyethylene glycol into solid-state nanopores

The intrusion of PEG aqueous solution into solid-state-nanopores upon mechanical pressure is experimentally investigated. By using hydrophobic nanoporous silica with a broad range of pore sizes, the characteristic size of PEG chains in water while penetrating nanopores is measured and analyzed, which increases with molecular weight and decreases with concentration of PEG. Its sensitivity to molecular weight is relatively limited due to nano-confinement. The inclusion of PEG as an intruding liquid imposes a rate effect on the intrusion pressure, and inhibits the extrusion from the nanopores.