Command of active matter by topological defects and patterns

A method for controlling at least one of a local concentration, trajectory, or net flow of self-propelled particles, comprising:

• providing a liquid crystal cell, the liquid crystal cell comprising in sequence:
• a first plate;
• a first photoalignment layer;
• a first alignment layer;
• a liquid crystalline medium;
• a second alignment layer;
• a second photoalignment layer;
• and
• a second plate;
• generating a spatially-distorted pattern via irradiation of the first photoalignment layer and the second photoalignment layer;
• polymerizing the first alignment layer and the second alignment layer and forming predesigned local ordering in the liquid crystalline medium;
• and
• providing the self-propelled particles to the liquid crystalline medium having predesigned local ordering.