Selective Janus Particle Assembly at Tipping Points of Thermally‐Switched Wetting

Thermal wetting can simply, selectively and reversibly join patchy particles into clusters (2D and 3D) and also colloidal crystals over the narrow temperature range of 1–2 °C. This is demonstrated with Janus particles (gold half‐coated silica spheres) immersed in a binary mixture of water/2,6‐lutidine, such that the relative strength of gold–gold bonding through hydrophobic interaction and silica–silica bonding through the wetting‐induced attraction is reversibly switched according to temperature.