Ultrahigh Damping Capacities in Lightweight Structural Materials

Abstract

The demand to outperform current technologies pushes scientists to develop novel strategies, which enable the fabrication of materials with exceptional properties. Along this line, lightweight structural materials are of great interest due to their versatile applicability as sensors, catalysts, battery electrodes, and acoustic or mechanical dampers. Here, we report a strategy to design ultralight (ρ = 3 mg/cm) and hierarchically structured ceramic scaffolds of macroscopic size. Such scaffolds exhibit mechanical reversibility comparable to that of microscopic metamaterials, leading to a macroscopically remarkable dynamic mechanical performance. Upon mechanical loading, these scaffolds show a deformation mechanism similar to polyurethane foams, and this resilience yields ultrahigh damping capacities, tan δ, of up to 0.47.

Freeze Casting: From Low‐Dimensional Building Blocks to Aligned Porous Structures—A Review of Novel Materials, Methods, and Applications

“…(C) Reproduced with permission. [ 71 ] Copyright 2018, American Chemical Society. (D) Reproduced with permission.…”

“…As another example of this, Knöller et al reported the ice‐templated fabrication of a ceramic‐based scaffold comprising V 2 O 5 nanofibers, mimicking the structure of cuttlebone, with good compressive properties at very low densities. [ 9a,71 ] Due to their very high void ratio, CNFA heterostructures, when infiltrated with water, can form unusual hydrogels. A CNFA structure formed by alginate bonded SiO 2 nanofibers was in recent work used to produce hydrogel materials accommodating high elastic deformations with strain sensitive conductivity.…”

“…The energy absorption efficiency and elastic response of a porous material can be greatly enhanced by imparting a structure of aligned pores, such as that found in freeze‐cast structures. [ 8f,22,41,42b,58,62e,71 ] The orientation and geometries of pores imparted by freeze‐casting govern dissipation and recovery during compressive strain. Knöller et al have in recent years reported various biomimetic scaffold structures based on vanadium pentoxide nanofibers.…”

“…Coupled with their unique arrangement, ultralight V 2 O 5 nanofiber based cellular networks fabricated by freeze casting have shown high damping capacity, exhibiting values of tan δ (loss factor, equal to the loss modulus divided by the storage modulus), of up to 0.47; damping performance which significantly exceeds existing materials(A–C). [ 71 ]…”

“…Reproduced with permission. [ 71 ] Copyright 2018, American Chemical Society. D) Real‐time images from high‐speed camera showing that C–G monolith can rebound a steel ball at large speed, in a spring‐like fashion.…”