Versatile Triblock Janus Nanoparticles: Synthesis and Self-Assembly

Abstract

Multiblock Janus nanoparticles (JNPs) are anisotropic particles composed of different blocks/lobes with distinct physicochemical properties. The ultimate goal is to obtain JNPs that carry two or more contrasting bulk and surface properties on different parts of the same particle. JNPs are promising candidates for various applications, such as building blocks for self-assembly and multifunctional materials. Here, we report the chemical synthesis of a special type of “versatile” triblock JNPs, which contain three lobes with different chemical compositions, whereby “versatile” means that the triblock JNPs can be separately and independently modified on at least two different lobes through different chemical reactions, offering limitless design possibilities. We further prove that specific chemical tailoring determines the way the JNPs interact and self-assemble, such that either normal or reverse micelles are obtained. In particular, the formation of micelles from triblock JNPs constitutes an initial example of the classical concepts extension from triblock polymers to colloids. We regard the triblock JNPs as representatives of a broader class of versatile anisotropic colloids, giving the ability to combine various functionalities on different parts of the same particle, thus enriching the tool box of nanomaterials and broadening their application potential.

Nanorobots: Machines Squeezed between Molecular Motors and Micromotors

“…76 Authors then showed the enhanced diffusion of the GOx/Ct Janus nanomotors in the biologic medium in the presence of various concentrations of glucose and use solely the MSD analysis of the particles' motion to prove enhanced diffusion of the Janus particles in the presence of glucose. Futher examples of Janus nanomotors include light-activated nanoparticles, 71,74 novel carriers as MOFs, 67 noble-metal composite nanoparticles, 75,78 bio-mimetic nanoparticles, 46,70 porous-silica based nanomotors, 80,60 polymeric capsules, 73 and cup-like structures. 43,68,79 Hollow Nanorobots Another type of nanomotor that has been extensively studied is the hollow particle with catalyst loaded inside.…”

“…The rules governing the engineered self-assembly of nanoparticles could also serve as strategies for reversible swarm behavior in large sets of individual nanorobots. 78,99…”

Janus Nanoparticles: From Fabrication to (Bio)Applications

“…JNPs consisting of two or more separate polymeric components have been extensively reported. ,− Polymeric components possess greater flexibility, customizable functionality, higher stability, and biocompatibility . Fickle structures have also been proposed, such as nanobowls, nanohats, nanocups, and nanocages. , Synthetic strategies for more representative polymeric JNPs are categorized (but not limited) into four main types: self-assembly strategy, phase separation strategy, seed-mediated polymerization synthesis strategy, and microfluidic synthesis strategy.…”

“…It is of importance that nanoparticles (NPs) with an asymmetric heterostructural junction at the micro/nanoscale provide many interesting properties, which are not approachable in symmetric or homogeneous nanostructures. For example, in the case of Fe 3 O 4 -Au JNPs, one part of Fe 3 O 4 NPs showed magnetic properties, whereas the other part of Au NPs possessed a localized surface plasmon resonance (LSPR) property. − The Janus structure allowed the combination of Fe 3 O 4 with Au, thereby providing a different surface polarity or interior chemistry compared to the corresponding single component, and further exhibited enhanced biomedical performance. , Over the past decades, JNPs have promptly extended from particles with two sides of opposite polarity to materials possessing various regions that have diverse compositions, − morphologies, − and properties. − JNPs have also exhibited superior performance in diverse of areas, for example, self-motile micro/nanomotors, compared to other NPs, including homogeneous sphere, yolk/shell nanostructures, core/shell nanostructures, hollow structures, etc.…”

Triphasic Polymer Particles Assembled via Microphase Separation with Multiple Functions

“…The asymmetric and dual-compartmentalized structures of JPs offer compelling access to various applications, including particulate surfactants, self-mobile particles, electric/magnetic field-driving devices, , and materials for bio/life science. , Progress in nanotechnology has made it possible to construct numerous JPs either by breaking the symmetry of existing particles or directly synthesizing smaller components into single particles. − Special methodologies have been developed to effectively fabricate JPs, such as subsequent surface modification, microfluidics, self-assembly of block copolymers, seeded polymerization, electrified cojetting, and microphase separation in the confined volume. − The push for further development is now facing new challenges of fabricating triphasic particles, which consist of three different parts with distinct features in the same particle. The triphasic particles have been successfully constructed in few cases, using colloid lithography, , seeded polymerization, microfluidics, , and electrified cojetting. , Among them, the in situ photoinitiated radical polymerization in microfluidics and seeded emulsion polymerization were used to synthesize ternary particles and triblock nanoparticles. , The colloidal spheres with three or more different zones were prepared through colloid lithography for the directed self-assembly. , In the processes of electrified jetting and electrohydrodynamic cospinning, a polymer solution containing three different dyes or fluorescent nanobeads was employed to demonstrate the multicompartmentalized effects. − However, a method via microphase separation in a confined volume, a feasible way to obtain discrete domains of different materials under an internal driving force, has not been adopted for the construction of ternary particles yet.…”