When gas rushes through solidifying foam to create porous polymers — used worldwide in insulation, packaging and sponges — it randomly scatters into bubbles of varying size.
Wiebke Drenckhan, a CNRS researcher at the University of Paris South, and her colleagues now report a way to create plastics filled with ordered and nearly uniform bubbles. The researchers combine chemical reagents, surfactants, air and water in such a way that bubbles form and pack together in the liquid phase just before the surrounding material 'freezes' in a polymerization reaction.
Working with German chemicals company BASF, in Ludwigshafen, they have created bubble-stuffed foam sheets and threads that absorb water and can even be woven or knitted into fabrics (pictured above). Such foams might be used as membranes, acoustic filters or shear-resistant wraps for fibres containing carbon nanotubes.