Extended Data Fig. 3: SVS fabrication through control of phase separation.

a, A scheme depicting the fabrication process of SVS. b, Cross-sectional SEM images of SVS samples show a gradual increase in the gradient degree of MAPP domains with the increase of the holding time. Insets present the corresponding confocal fluorescence images. To enhance the visibility of the MAPP phase, the concentration of MAPP components was increased to 5 wt% for this characterization. The gradient distribution of the MAPP phase in the SIBS network can be adjusted by regulating the holding time of the mixing solution during the second step shown in (a). When holding time was short, MAPP condensates did not coalesce, leading to the formation of numerous MAPP nanodomains within the SIBS network. With the prolongation of the holding time, MAPP gradually aggregated and settled towards the bottom of the substrate, creating a micro/nano-confined space between the substrate and the MAPP domains. Upon the evaporation of the solvent, these MAPP domains were locked in a phase-separation state with PP chains entangled with PIB segments in SIBS. Extending the holding time to 24 hours caused a complete separation of MAPP from the SIBS matrix, resulting in defective interfaces between the MAPP domain and the SIBS matrix. c, Schematics of the homogenous SIBS/MAPP, SVS, and layer-like SIBS/MAPP films.