Figure 1. Mechanism of nanostructure reconfiguration in a medium.

(a) Schematic of the nanoassembly process, which consist of the following: an initial state where NPs are randomly distributed, a transition state where NPs migrate to lower-energy configurations and a final assembly state where NPs are located in new stable positions (Supplementary Movie 1). (b) Rheology of a typical thermoplastic (for example, the complex shear modulus (G′+i G″) of pHEMA changes from 1.4 × 10⁹+i 2.0 × 10⁷ Pa in the glassy regime to 2.9 × 10⁴+i 2.0 × 10⁴ Pa well above its glass transition temperature (T_g) of 300 °C). (c) Time-dependent temperature at the surface of NPs of different diameters from a pulsed laser 532 nm, 5 ns and 20 mJ cm⁻² (this is equivalent to the temperature produced by two interfering waves of 10 mJ cm⁻² at the maximum gradient point). (d) Dynamics of NP displacement in a standing wave. (e) Relative maximum force acting on Ag NPs of different diameters with a standing wave of 532 nm. (f) Potential wells produced by the interference of counter-propagating waves.