Reversible photo-controlled mass transfer in a photo-responsive conjugated main-chain polymer film for high contrast surface patterning

A pi -conjugated polymer containing an azobenzene segment in its backbone is found to be highly photo-responsive. As the polymer film is irradiated with an interfering laser beam, the trans-to cis- photo-isomerization in the polymer chain induces a great change to the chain configuration from a rigid-rod to an irregular coil, and a corresponding great local stress, which drives the chain transfer to form high contrast surface patterning.