Fig. 1: Multiple kinetics-dynamics engineering of phenolic nanostructures.

a Schematic diagrams of phenolic growth kinetics, inflation-deflation kinetics, and interfacial polymerization kinetics. Yellow dots represent phenolic small-molecule polymers, while yellow irregular shapes denote the transition from small-molecule clusters to large-molecule phenolic aggregates. Pink spheres represent phenolic large-molecule polymers. Blue arrows illustrate the process of particle deflation and depression, whereas orange arrows depict the phenomenon of particle inflation and expansion. The ultrasonic environment is indicated by the blue background, complemented by white lines that symbolize the ultrasonic waves. b Changing the solution temperature modulates the phenolic growth kinetics. Scanning electron microscopy (SEM) images and dynamic light scattering spectra of phenolic resin nanoparticles (PRNs) obtained at different solution temperatures. The inside yellow spheres indicate phenolic small-molecule polymers that can be etched by acetone. c Acetone as a low molecular polymer etchant to verify the gradient polymerization degree due to phenolic growth kinetics. The gel permeation chromatography and transmission electron microscope (TEM) images of PRNs etched with different acetone/water ratios. Mn is number-average molecular weight. d Too high or too low a concentration of ammonia can disrupt phenolic growth kinetics. TEM images of different ammonia content. Irregular yellow kernels indicate that it is not all small-molecule polymers, which acetone cannot etch completely. e Phenolic growth in an ethanol solution results in the formation of porous structures due to localized early dissolution of small molecule polymers. Solid state nuclear magnetic resonance ¹³C spectra obtained from ethanol-modified phenolic growth kinetics, and TEM images of porous PRNs (p-PRNs) and porous hollow PRNs (ph-PRNs). f The rapid etching action of acetone resulted in rapid shrinkage of the particles and slow expansion over the next 30 minutes. Etching time-dominated modulation of inflation-deflation dynamcs achieves bowl-to-spherical transient capture. TEM images of bowl-shaped hollow PRNs (bh-PRNs) obtained from inflation-deflation dynamics. g Ultrasonic power modulates the interfacial polymerization kinetics of phenolics. TEM images of short chain-shaped PRNs (c-PRNs) and short chain-shaped hollow PRNs (ch-PRNs) obtained from interfacial polymerization dynamics. The scale of above SEM images and TEM images is 200 nm.