Hierarchical Assemblies of Polymer Particles through Tailored Interfaces and Controllable Interfacial Interactions

Abstract

Hierarchical assembly architectures of functional polymer particles are promising because of their physicochemical and surface properties for multi‐labeling and sensing to catalysis and biomedical applications. While polymer nanoparticles’ interior is mainly made up of the cross‐linked network, their surface can be tailored with soft, flexible, and responsive molecules and macromolecules as potential support for the controlled particulate assemblies. Molecular surfactants and polyelectrolytes as interfacial agents improve the stability of the nanoparticles whereas swellable and soft shell‐like cross‐linked polymeric layer at the interface can significantly enhance the uptake of guest nano‐constituents during assemblies. Besides, layer‐by‐layer surface‐functionalization holds the ability to provide a high variability in assembly architectures of different interfacial properties. Considering these aspects, various assembly architectures of polymer nanoparticles of tunable size, shapes, morphology, and tailored interfaces together with controllable interfacial interactions are constructed here. The microfluidic‐mediated platform has been used for the synthesis of constituents polymer nanoparticles of various structural and interfacial properties, and their assemblies are conducted in batch or flow conditions. The assemblies presented in this progress report is divided into three main categories: cross‐linked polymeric network's fusion‐based self‐assembly, electrostatic‐driven assemblies, and assembly formed by encapsulating smaller nanoparticles into larger microparticles.

Four-Level Structural Hierarchy: Microfluidically Supported Synthesis of Polymer Particle Architectures Incorporating Fluorescence-Labeled Components and Metal Nanoparticles

“…After synthesis of individual building blocks, the primary assemblies were formed by mixing negatively charged gold nanoparticles and PMMA particles with a positively charged surface layer of pDADMAC. Assemblies based on an electrostatic interaction can be influenced strongly by particle concentration, reaction time, temperature and volume ratio of particles . One of the most important conditions for an efficient composite formation is the right ratio between the two types of particles.…”

“…To form a uniform and systematic assembly, the particle size and surface charge are the most important characteristics. , Other essential factors are the balance of attractive and repulsive interactions between particles and also interfacial interactions between particles and their surroundings. Electrostatic interactions can be used to assemble charged nanoparticles into higher-order structures.…”

“…Surface-active agents must be applied for an appropriate control of the state of the nanoparticle surfaces to achieve high stability and avoid uncontrolled random aggregation in the solution phase . Also, the layer-by-layer (LBL) functionalization approach is beneficial for modifying the surface properties, such as the ζ potential, and for introducing functional groups and allows tunability of the assembly system . Other beneficial features can be created by embedding fluorescent dyes into polymer nano- and microparticles.…”

General Background of SERS Sensing and Perspectives on Polymer‐Supported Plasmon‐Active Multiscale and Hierarchical Sensor Particles

“…Functionally graded hierarchical structures made up of the nanoscale building blocks can be prepared in the whole spectrum of size range between smaller individual nanoparticles of about 10 nm and larger composite particles of about 1 mm. [ 168 ]…”

Intercluster Exchange-Stabilized Novel Complex Colloidal χc Phase

“…Although several examples of χ phase have been identified in metal alloys, ultrathin gold nanowires, and high-pressure methane B , constructing χ phase using simple and experimentally realizable surface-anisotropic colloidal building blocks and clarifying its formation mechanism have so far remained largely elusive. Moreover, the complex colloidal χ phase may enable potential applications in the fields of structural color palettes, − hybrid materials, , electronic paper display, , and multifunctional materials. − Therefore, we regard the χ phase as our target structure.…”