Bulk Nanoporous Metal for Actuation

Abstract

Nanoporous metals prepared by controlled chemical or electrochemical corrosion of alloys can provide prototypical manifestations of bulk nanostructured material. Samples are readily prepared with dimensions at the millimeter or centimeter scale, while at the same time the microstructure is a homogeneous array of interpenetrating solid skeleton phase and pore channels with a characteristic size that can reach down to below 5 nm. The interest in nanoporous metals as functional materials derives from recent observations of unique materials behavior resulting from their extremely small structure size and their open porosity with large volume‐specific surface area. As an example, this article discusses the possible use of nanoporous metal for actuation.

Fast and Reversible Actuation of Metallic Muscles Composed of Nickel Nanowire‐Forest

“…[10,11] Yet, current metallic actuators remain mainly noble metals such as Au and Pt, [2,12,13] while robust actuation with less costly and technologically more relevant metal remains to be demonstrated. [14] Here, we describe a strategy to fabricate cantilever actuators from nanoporous Ni, a low-cost metal. We demonstrate fast strain response (order of 0.1 s) with sustainable actuation performance (no noticeable degradation after 800 cycles) and with a strain energy compatible with skeletal muscles.…”

Dealloying progress during nanoporous structure evolution analyzed by in situ resistometry

“…1 By this method bulk quantities of nanoporous (np) metals can be produced, which find application in different fields of science and technology, ranging from energy storage 2,3 and (electro-)catalysis [4][5][6][7][8] to sensing [9][10][11][12] and electrochemical property tuning. [13][14][15][16][17][18][19] Dealloying is known to occur in a variety of different alloy systems, ranging from simple solid solution binary alloys 1,20 to more complex systems such as intermetallic compounds 21,22 or ternary alloys. 23,24 By far the most intensively studied dealloyed material is nanoporous gold (np-Au), selectively etched from solid solution Ag-Au master alloys, 1 with typical pore sizes in the range of tens of nanometers.…”

Charge-Induced Reversible Bending in Anodic Porous Alumina–Aluminum Composites

“…Recently, charge-induced reversible straining was also observed in nanoporous noble metals [4], such as Pt [4], Au [5], and Au-Pt alloys [6], which are becoming a promising type of electrochemical actuators for potential applications such as artificial muscles [7]. The mechanism behind the chargeinduced reversible straining in nanoporous metals is understood as follows [4,6,8]. When the nanoporous metal becomes an electrode within an electrochemical cell, an electrochemical double layer is formed along the metal surface, and due to the efficient electronic screening [4], space charge is developed within the metal surface, which contributes to one half of the electrochemical double layer [8].…”