Devices and methods for spatially and temporally reconfigurable assembly of colloidal crystals

A method for making a device for controlled assembly of colloidal particles, the method comprising:

• disposing a medium comprising a plurality of colloidal particles having a charged surface, in contact with an electrically conductive material capable of receiving light from an external light source to form the device, wherein the plurality of colloidal particles in the device can be reversibly driven from a first non-assembled state to a second assembled state when the light is activated from the external light source and directed to the electrically conductive material, wherein a transition from the first non-assembled state to the second assembled state is reversible and occurs without any external electric fields or external magnetic fields.

A method of making a device for controlled assembly of colloidal particles, comprising:

• disposing a medium comprising a plurality of colloidal particles having a charged surface in contact with an electrically conductive material to create the device, wherein the medium has a dielectric constant of less than about 80 and the charged surface of the colloidal particle has a ζ-potential of greater than or equal to about −100 mV to less than or equal to about 100 mV, wherein the device is configured to receive light from an external light source, so that in the absence of the light, the plurality of colloidal particles is in a first non-assembled state and in the presence of the light, the plurality of colloidal particles is reversibly driven into a second assembled state, where the device has no external electric fields or external magnetic fields.