Electrically controllable device having variable diffusion by liquid crystals, and method for same

An electrically controllable device having scattering which is variable by liquid crystals comprising a stack of layers in this order:

• a first electrode with a first main surface forming a bonding surface and an opposite surface,
• a dielectric electroactive layer with a main face on the bonding surface side and a main opposite face, made of a material comprising:
• liquid crystals,
• polymers forming a polymeric network, the liquid crystals being stabilized by the polymeric network,
• a second electrode with, on the side of the opposite face of the dielectric electroactive layer, a main surface forming a second bonding surface and with an opposite surface, the electroactive layer being visible by transparency on the side of the first electrode or on the side of the second electrode, or both,
• wherein the material exhibits, starting from a temperature T1, a mesophase P in which the material comprises an assembly of subcentimetric domains, which comprise two-dimensional topological defects,
• and wherein, at a temperature T′ greater than or equal to T1, the stack is capable of exhibiting at least first, second and third scattering states for at least one wavelength in the visible region,
• the first state being scattering and the most scattering,
• the second state being scattering and less scattering than the first state, and the third state being transparent or scattering and less scattering than the second state, the first, second and third states being switchable,
• at least two of the first, second and third states being obtained by the application of an electric field between the first and second electrodes.