A novel response materializes.

The article reports that researcher Joanna Aizenberg has developed a combination of rigid silicon nanocolumns embedded in a hydrogel layer, which results in reversibly actuated surface nanostructures that alter their orientation in response to external stimuli, forming controlled and complex microstructures. Two different configurations were produced. The materials started out as an array of isolated, high-aspect-ratio rigid structures (AJRS). The silicon nanocolumns had diameters of 100-300 nm and heights of 5-8 pm. A polyacrylamide gel (PAAG) layer was then formed in the space between the AIRS and a secondary substate to make a hydrogel-AIRS (HAIRS) assembly.