Origami with molecules?

By Udit Chaudhuri

Photograph courtesy:  Jongmin Shim, Katia Bertoldi and Pedro Reis

A building with collapsible walls and roofs, an arm with smooth, seamless joints like a green branch instead of mechanical pairs, a micro-sized drug delivery system digging into a specific gland or a ‘paste’ that forms into a defined shape may well become a reality quite soon!

Progress in the materials sciences sees attempts to ‘design’ molecular patterns and thus micro-sized forms. However, there are limitations that hold up scaling this up to visible objects of our daily use. I am referring to the Buckliball-inspired experiment at Harvard and MIT.

Katia Bertoldi, Assistant Professor of Applied Mechanics at the Harvard School of Engineering & Applied Sciences (SEAS), 
with Postdoctoral Fellow Jongmin Shim. Photograph by Eliza Grinnell, Harvard SEAS.

A team of scientists at MIT and Harvard led by Katia Bertoldi, Assistant Professor in Applied Mechanics at Harvard; and Pedro Reis, the Esther and Harold E. Edgerton, Assistant Professors of Civil and Environmental Engineering and Mechanical Engineering at MIT wrote about this work now published in Proceedings of the National Academy of Sciences. Inspired by the Buckliball, a toy ball made of complex hinged joints that folded this ball into becoming a smaller one, the team ‘constructed’ a soft rubber ball. Inter-molecular air sucked out of it, saw the ball form dimples and churn itself akin to the Buckliball into a smaller shrivelled ball, in an orderly way.  

Playing with an expanding and collapsing toy (top row), researchers at Harvard and MIT were inspired

 to design a new type of folding structure. The result is a one-piece silicone sphere, dubbed a "buckliball" for its

pressure-induced buckling behavior (bottom row). Photograph courtesy: Katia Bertoldi.

In origami, it has been possible to turn and collapse cubes and polygonal prisms by valley-folding their faces diagonally and twisting them into becoming compact paper springs. This experiment now makes for such “Buckligami” behaviour. It will be possible to build structures of molecules or compounds, albeit presently in soft materials, that will collapse in an orderly way under pressure and then build back to their original form when such pressure reverses. Practical applications could extend to include robotic skins and fibres, collapsible roofs and walls, controlled bending of beams or paste morphing back to an original shape on being released from a vacuumed dispenser as well as specialised drug delivery systems.

The Buckliball
Video: Lucy Lindsey/Melanie Gonick; footage courtesy of Jongmin Shim, Katia Bertoldi and Pedro Reis

Information Courtesy:

1.        Denise Brehm, Civil and Environmental Engineering Dept, Massachusetts Institute of Technology, USA.

2.       Caroline Perry, Harvard School of Engineering and Applied Science, Harvard University, USA.