Shaping Nanoscale Ribbons into Micro-Helices of Controllable Radius and Pitch

TL;DR

This paper introduces a versatile method to fabricate highly flexible nanoscale ribbons into micro-helices with controllable radius, length, and pitch, using surface tension and material creep properties across various materials.

Contribution

The study demonstrates a novel fabrication technique for micro-helices from nanoribbons with independent control over geometric parameters and material versatility.

Findings

Helices can be shaped with radius 1-100 micrometers, length 100-3000 micrometers, and pitch angle 0-70°.

Method validated on polymers, hydrogels, and nanoparticle arrays, showing broad material applicability.

Helical structures exhibit tunable mechanical properties based on material choice and geometry.

Abstract

We report fabrication of highly flexible micron-sized helices from nanometer-thick ribbons. Building upon the helical coiling of such ultra-thin ribbons mediated by surface tension, we demonstrate that the enhanced creep properties of highly confined materials can be leveraged to shape helices into the desired geometry with full control of the final shape. The helical radius, total length and pitch angle are all freely and independently tunable within a wide range: radius within $\sim$ 1-100 micrometer, length within $\sim$ 100-3000 micrometer, and pitch angle within $\sim$ 0-70{\deg}. This fabrication method is validated for three different materials: poly(methyl methacrylate), poly(dimethylaminoethyl methacrylate), and transition metal chalcogenide quantum dots, each corresponding to a different solid-phase structure: respectively a polymer glass, a crosslinked hydrogel, and a nanoparticle array. This demonstrates excellent versatility with respect to material selection, enabling further control of the helix mechanical properties.