New Substrates

Nanocardboard

A team of Penn Engineers has recently demonstrated a new material they call «nanocardboard,» an ultrathin equivalent of corrugated paper cardboard. Igor Bargatin, Class of 1965 Term Assistant Professor of Mechanical Engineering and Applied Mechanics, along with lab members Chen Lin and Samuel Nicaise, led the study. They collaborated with Prashant Purohit, professor in Mechanical Engineering and Applied Mechanics, and his graduate student Jaspreet Singh, as well as Gerald Lopez and Meredith Metzler of the Singh Center for Nanotechnology. Bargatin lab members Drew Lilley, Joan Cortes, Pengcheng Jiao and Mohsen Azadi also contributed to the study. The results were published in the journal Nature Communications1. A square centimetre of nanocardboard weighs less than a thousandth of a gram and can spring back into shape after being bent in half. Nanocardboard’s stiffness-to-weight ratio makes it ideal for aerospace and microrobotic applications, where every gram counts. In addition to un­precedented mechanical properties, nanocardboard is a supreme thermal insulator, as it mostly consists of empty space. Future work will explore an intriguing phenomenon that results from a combination of properties: shining a light on a piece of nanocardboard allows it to levitate. Heat from the light creates a difference in temperatures between the two sides of the plate, which pushes a current of air molecules out through the bottom.

University of Pennsylvania, Philadelphia, PA 19104 USA, www.upenn.edu