Flexible Ultrastrong 100-nm Polyethylene Membranes with Polygonal Pore Structures

TL;DR

This paper reports the fabrication of a novel, ultrastrong, flexible 100-nm polyethylene membrane with polygonal pores, suitable for advanced technological applications like sensors and artificial skins.

Contribution

It introduces a new method to create ultrastrong, flexible polyethylene membranes with unique pore structures, surpassing previous ultrathin film strength limitations.

Findings

Membrane tensile strength is approximately 900 MPa.

The membrane exhibits 26% ductility.

Successfully applied as a conformable piezoresistive sensor.

Abstract

Robust nanoporous polymer films with approximate 100-nm thicknesses would be broadly applicable in technological areas such as flexible sensors, artificial skins, separators, antireflection and self-cleaning films. However, the creation of these films has been extremely challenging. To date, all reported ultrathin films are of insufficient mechanical strength for use without substrate supports. We describe here the fabrication of a new ultrastrong and highly flexible ultrahigh molecular weight polyethylene (UHMWPE) 100-nm porous membrane. Scanning and transmission electron microscopy evaluations of film microstructures reveal a planar fibrous structure with randomly oriented polygonal interconnected pores. Moreover, the tensile strength of this film is twice as strong as that of solid stainless steel, with a measured in-plane tensile strength and ductility of approximately 900 MPa and 26%, respectively. We further coated our newly developed film with a monolayer graphene to invent an optically transparent and fully conformable piezoresistive skin sensor and thus demonstrated a potential application.