Optical switching of hierarchical self-assembly: Towards "enlightened" materials

Several important design aspects including the utility of covalent-bond formation to freeze-in specific conformations caused by supramolecular organization and the advantage of reversible structural changes within photochromatic compounds to direct hierarchical self-assembly are illustrated. The system allows one to repeatedly cycle between four distinct switching states that can easily be read out due to different chiro-optical properties and offers potential for development of memory systems. Controlling diffusion processes in the gels by means of advanced optics such as holographic grating techniques, offers a new way to reversibly pattern substrates. The use of structural changes in photochromic building blocks to affect their self-assembly behavior and therefore modulate macroscopic properties where low-molecular-weight gelators based on chiro-optical switch with appended hydrogen bonding units have been described.