Multicompartment micelles are an intriguing class of self-assembled aggregates with subdivided solvophobic cores. They have been subject to extensive research in part due to their unique morphological and sequestration properties as a result of multiple distinct chemical environments being in close proximity within one nanostructure. Multicompartment micelles hold potential for use in various applications that include the therapeutic delivery of multiple incompatible drug payloads. The present Perspective reviews recent achievements in strategies for the synthesis, self-assembly, and morphological control of multicompartment micelles and highlights future challenges and potential applications.

A quaternary amine end functionalised diblock copolymer (PtBuA-b-PNIPAM) has been synthesised using RAFT polymerisation and shown to undergo a thermally induced morphology transition from micelles to vesicles, as evidenced by TEM, AFM, SLS and DLS analyses.

An SCS "pincer"-based nitroxide-mediated polymerization (NMP) initiator has been synthesized and utilized to polymerize tert-butyl acrylate ( ( t )BuA), affording polymers with control over molecular weight and polydispersity. (1)H NMR spectroscopy indicates that the sulfur end group remains intact after deprotection of the P ( t )BuA segment to yield a poly(acrylic acid) segment. The hydrophilic polymer-tethered SCS ligand has been demonstrated to bind to palladium(II), as characterized by a distinctive Pd-C shift in the (13)C NMR spectrum and a diagnostic metal-to-ligand charge-transfer band in the UV-vis spectrum. A pyridine-functionalized NMP initiator has also been synthesized and used to initiate the NMP of styrene with good control and end group fidelity. The binding of these two chain end ligand-functionalized polymers to form an amphiphilic metallosupramolecular diblock copolymer is facile, as indicated through extended (1)H and (13)C NMR studies. The self-assembly of this diblock into well-defined, monodisperse, noncovalently connected micelles (NCCMs) is reported and has been characterized by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. The NCCMs were selectively stabilized throughout the shell layer to produce stable noncovalently connected nanoparticles, resulting in a distinctive reduction in the solution hydrodynamic radius and zeta potential compared to those of the precursor micelle. The hydrophobic core domain was then readily removed via dialysis at low pH to afford a hollow polymeric nanocage with well-defined interior functionality. A significant increase in the solution hydrodynamic radius and shape by AFM analysis was observed upon removal of the core, and the hydrophilic nanocages were shown to be ineffective in the sequestration of hydrophobic dye molecules relative to the parent nanoparticle.

The design and synthesis of a tuneable and reversible morphology switching copolymer system is reported. The kinetics of the transition under a range of conditions has been explored, as has the stabilization of the resultant structures.

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We present the synthesis of novel core reactive spherical polymeric micelles and nanoparticles using nitroxide mediated polymerization (NMP) techniques. These nanostructures have terpyridine functionality selectively located within their hydrophobic core domain and have been further modified by metal complexation (with Fe, Ru, and Cu) within this domain to afford novel metal functionalized polymer nanostructures. The hydrodynamic diameters (D h) of these micelles and hybrid nanoparticles were determined by dynamic light scattering (DLS), and the dimensions of the nanoparticles were characterized using transmission electron microscopy (TEM) and confirmation of the complexation was achieved using UV–vis analysis. The reactivity of the Cu-tethered metal complex within the nanostructures was investigated and was found to be an active catalyst for the 1,3-dipolar cycloaddition “click” reaction of azido and alkynyl functionalized small molecules. This strategy provides a versatile synthetic route toward the selective incorporation of active sites within the core domain of a polymer nanoparticle.

Many research groups have explored the properties and solution self-assembly of main chain metallo-supramolecular multiblock copolymers. Until recently, these metal complexes have been used to prepare mainly micelle type structures. However, the self-assembly of such copolymers has been exploited further to create more advanced architectures which utilize the reversible supramolecular linkage of their building blocks as a key component in their synthesis. Furthermore, the incorporation of multiple orthogonal interactions and stimuli responsive polymers into their design, enables more precise external control of their properties. This feature article discusses recent developments and provides an insight into their potential exploitation and development for the creation of novel, smart, and responsive nanostructures.

We report the aqueous solution self-assembly of a series of poly(N-isopropylacrylamide) (PNIPAM) polymers end-functionalized with a hydrophobic sulfur-carbon-sulfur (SCS) pincer ligand. Although the hydrophobic ligand accounted for <5 wt% of the overall homopolymer mass, the polymers self-assembled into well-defined spherical micelles in aqueous solution, and these micelles are potential precursors to solution-assembled nanoreactors for small molecule catalysis applications. The micelle structural details were investigated using light scattering, cryogenic transmission electron microscopy (cryo-TEM), and small angle neutron scattering (SANS). Radial density profiles extracted from the cryo-TEM micrographs suggested that the PNIPAM chains formed a diffuse corona with a radially decreasing corona density profile and provided valuable a priori information about the micelle structure for SANS data modeling. SANS analysis indicated a similar profile in which the corona surrounded a small hydrophobic core containing the pincer ligand. The similarity between the SANS and cryo-TEM results demonstrated that detailed information about the micelle density profile can be obtained directly from cryo-TEM and highlighted the complementary use of scattering and cryo-TEM in the structural characterization of solution-assemblies, such as the SCS pincer-functionalized homopolymers described here.