Self-assembling capsules: From molecular recognition to hydrogen-bonded liquid crystals and fibers

"Tennis balls", "softballs", and "footballs" can all be self-assembled from appropriately shaped molecules via hydrogen bonding. The assembly and uses of these capsules as hosts and catalysts are surveyed as are the liquid-cr ystalline and fibrous properties of hydrogen-bonded capsule polymers, or po lycaps - promising alternatives to covalent polymers. The Figure shows the mechanism of guest exchange in a capsule.