Controlled Folding of Micrometer-Size Structures

TLDR

Microactuators have been fabricated in various forms, ranging from simple paddles to self‑assembling and disassembling cubes. The devices use polymer–gold bilayer hinges to connect rigid plates to a silicon substrate, and are released by a differential‑adhesion technique that eliminates the need for a sacrificial layer. Electrically controlled, reversible hinge bending enables precise 3‑D positioning of plates, and the differential‑adhesion release method—free of sacrificial layers—offers general micromachining applications such as switchable reflective or chemical surface properties.

Abstract

Several types of microactuators have been fabricated, from simple paddles to self-assembling and -disassembling cubes. Conducting bilayers made of a layer of polymer and a layer of gold were used as hinges to connect rigid plates to each other and to a silicon substrate. The bending of the hinges was electrically controlled and reversible, allowing precise three-dimensional positioning of the plates. The structures were released from the substrate with a technique based on differential adhesion. This method, which avoids the use of a sacrificial layer and allows the actuators to pull themselves off the surface, may have general applications in micromachining. Possibilities include the manufacture, of surfaces whose light reflection or chemical properties can be switched.