Fig. 2: Interfacial microphase domain structure and dynamics.

CLSM fluorescence images showing a single DTAF-labeled (green fluorescence) PVA-coated tributyrin microdroplet before bleaching (left) and 0.3 (middle) and 30 s (right) after laser-induced bleaching (a); corresponding CLSM images for a single DTAF-labeled BSA-coated tributyrin microdroplet before bleaching (left) and 30 (middle) and 600 s (right) after bleaching are shown in (b). The laser-induced bleaching is highly localized (orange circles); non-activated regions (control) are also shown (blue circle). c, d Corresponding FRAP profiles showing time-dependent changes in fluorescence intensity (FI) recorded from the orange and blue circles shown in (a and b), respectively. Fluid and gel-like states are observed for the PVA and BSA surface layers, respectively. e Diffusion coefficients of PVA and BSA at the tributyrin/water interface confirming the gel or fluid states of the microphase-separated BSA or PVA domains, respectively. f Plots of complex modulus (E*) and viscosity of BSA and PVA microphases at pH = 7 and 3 (BSA only) at the air/water interface. CLSM fluorescence images for oil droplets with BSA (g) or PVA (h) continuous phases showing immobile or mobile microphase-separated PVA and BSA domains, respectively; Insets: Enlarged view of the yellow dashed area; RBITC-BSA, red fluorescence. i Changes of Pearson’s correlation coefficient (PCC) over time showing the relationship of the microphase-separated state compared to the initial states. A PCC value close to 1.0 indicates that the fluorescence signals recorded at the same positions at different times and at time t = 0 are highly overlapping, while fluorescence signals approaching zero indicate that the two fluorescence signals are not correlated. The PCC values maintain near to 1.0 over time, which demonstrate that the relative position of the PVA domains did not change. The PCC values gradually decrease to zero due to changes in the relative positions of the discontinuous BSA domains. Data in (c–f) and (i) are presented as mean values ± SD, error bars indicate standard deviations (n = 3 independent experiments). All relevant experiments are performed independently three times with similar results. Source data are provided as a Source Data file.