Fabrication of Polyhedral Particles from Spherical Colloids and Their Self‐Assembly into Rotator Phases

Particle shape is a critical parameter that plays an important role in self‐assembly, for example, in designing targeted complex structures with desired properties. Over the last decades, an unprecedented range of monodisperse nanoparticle systems with control over the shape of the particles have become available. In contrast, the choice of micrometer‐sized colloidal building blocks of particles with flat facets, that is, particles with polygonal shapes, is significantly more limited. This can be attributed to the fact that in contrast to nanoparticles, the larger colloids are significantly harder to synthesize as single crystals. It is now shown that a very simple building block, such as a micrometer‐sized polymeric spherical colloidal particle, is already enough to fabricate particles with regularly placed flat facets, including completely polygonal shapes with sharp edges. As an illustration that the yields are high enough for further self‐assembly studies, the formation of three‐dimensional rotator phases of fluorescently labelled, micrometer‐sized, and charged rhombic dodecahedron particles was demonstrated. This method for fabricating polyhedral particles opens a new avenue for designing new materials.     

Kinetic Control of Aggregation Shape in Micellar Self‐Assembly

The first steps towards top‐down morphology control in micellar self‐assembly are introduced. Kinetically stable micelles are formed from block copolymers (BCPs) using continuous flow techniques by turbulent mixing of water with a THF solution of polymers. In this way, particle shape and size can be altered from spheres to ellipsoids solely via tuning of mixing parameters from a single BCP.     

Microenvironment‐Induced In Situ Self‐Assembly of Polymer–Peptide Conjugates That Attack Solid Tumors Deeply

In cancer treatment, the unsatisfactory solid‐tumor penetration of nanomaterials limits their therapeutic efficacy. We employed an in vivo self‐assembly strategy and designed polymer–peptide conjugates (PPCs) that underwent an acid‐induced hydrophobicity increase with a narrow pH‐response range (from 7.4 to 6.5). In situ self‐assembly in the tumor microenvironment at appropriate molecular concentrations (around the IC₅₀ values of PPCs) enabled drug delivery deeper into the tumor. A cytotoxic peptide KLAK, decorated with the pH‐sensitive moiety cis‐aconitic anhydride (CAA), and a cell‐penetrating peptide TAT were conjugated onto poly(β‐thioester) backbones to produce PT‐K‐CAA, which can penetrate deeply into solid tumors owing to its small size as a single chain. During penetration in vivo, CAA responds to the weak acid, leading to the self‐assembly of PPCs and the recovery of therapeutic activity. Therefore, a deep‐penetration ability for enhanced cancer therapy is provided by this in vivo assembly strategy.     

Staged Surface Patterning and Self‐Assembly of Nanoparticles Functionalized with End‐Grafted Block Copolymer Ligands

Using two orthogonal external stimuli, programmable staged surface patterning and self‐assembly of inorganic nanoparticles (NPs) was achieved. For gold NPs capped with end‐grafted poly(styrene‐block‐(4‐vinylbenzoic acid)), P(St‐block‐4VBA), block copolymer ligands, surface‐pinned micelles (patches) formed from NP‐adjacent PSt blocks under reduced solvency conditions (Stimulus 1); solvated NP‐remote P(4VBA) blocks stabilized the NPs against aggregation. Subsequent self‐assembly of patchy NPs was triggered by crosslinking the P(4VBA) blocks with copper(II) ions (Stimulus 2). Block copolymer ligand design has a strong effect on NP self‐assembly. Small, well‐defined clusters assembled from NPs functionalized with ligands with a short P(4VBA) block, while NPs tethered with ligands with a long P(4VBA) block formed large irregularly shaped assemblies. This approach is promising for high‐yield fabrication of colloidal molecules and their assemblies with structural and functional complexity.     

Shape‐Assisted Self‐Organization in Highly Disordered Liquid Crystal Phases

In achiral rod‐like molecules, a nematic phase is the most disordered liquid crystal phase, which only has one‐directional order in the direction of the molecular long axis. A dumbbell‐shaped molecule (compound 3 : R−C₆H₁₀−CH=CH−C₆H₄−CH=CH−C₆H₁₀−R, (R=n C₅H₁₁)), and its liquid crystal phase (X phase) are reported, which exhibit high scattering without thermal fluctuation between two nematic phases under a polarized light optical microscope. The X phase was investigated by X‐ray diffraction, scanning electron microscopy, atomic force microscopy, and molecular dynamics simulation. A layered structure was ascertained for which a molecular self‐organization mechanism was postulated in which the super‐structure is based on lateral intermolecular interlocking. A second nematic phase above the X phase consisted of “rice grain”‐shaped particles.     

Aqueous Self‐Assembly of Y‐Shaped Amphiphilic Block Copolymers into Giant Vesicles

The preparation and aqueous self‐assembly of newly Y‐shaped amphiphilic block polyurethane (PUG) copolymers are reported here. These amphiphilic copolymers, designed to have two hydrophilic poly(ethylene oxide) (PEO) tails and one hydrophobic alkyl tail via a two‐step coupling reaction, can self‐assemble into giant unilamellar vesicles (GUVs) (diameter ≥ 1000 nm) with a direct dissolution method in aqueous solution, depending on their Y‐shaped structures and initial concentrations. More interesting, the copolymers can self‐assemble into various distinct nano‐/microstructures, such as spherical micelles, small vesicles, and GUVs, with the increase of their concentrations. The traditional preparation methods of GUVs generally need conventional amphiphilic molecules and additional complicated conditions, such as alternating electrical field, buffer solution, or organic solvent. Therefore, the self‐assembly of Y‐shaped PUGs with a direct dissolution method in aqueous solution demonstrated in this study supplies a new clue to fabricate GUVs based on the geometric design of amphiphilic polymers.

     

A Novel and Efficient One‐Pot Synthesis of 2‐Aminopyrimidinones and Their Self‐Assembly

A three‐component reaction of benzaldehyde derivatives, methyl cyanoacetate, and guanidinium carbonate affords 2‐amino‐4‐aryl‐1,6‐dihydro‐6‐oxopyrimidine‐5‐carbonitriles and the four‐component reaction of benzaldehyde derivatives, methyl cyanoacetate, and guanidinium hydrochloride in the presence of piperidine leads to piperidinium salts of pyrimidinones. X‐ray crystallography data confirm self‐assembly and H‐bonding in these compounds.     

Cyclic Peptide–Polymer Complexes and Their Self‐Assembly

Pepped up polymers : The synthesis and properties of novel chiral cyclic peptides designed to complex with suitable polymers through hydrogen bonding are described. A substituted cyclic peptide self‐assembles into supramolecular nanotubes and develops noncovalent interactions with poly(vinyl alcohol) (PVA) by means of its carboxyl side chains.

     

An Unconventional Approach to Induce Liquid‐Crystalline Phases of Triazine‐Based Dendrons by Breaking Their Self‐Assembly into Dimers

Three triazine‐based dendrons ( 1 a – c ) were successfully prepared in 70–83 % yields. These newly prepared dendrons are found to be liquid crystalline (LC). Computational investigations on molecular conformations and dipoles of triazine‐based dendrons reveal that the substituent on the central triazine unit interrupts strong dipole or H‐bond interactions to avoid dimeric formation. The obtained dendrons, not favouring self‐assembly into dimers but showing LC behaviours, provides evidence for an approach contrary to the conventional method of inducing LC behaviours of dendrons by dimer or trimer formation, mostly through H‐bond interactions.     

Access to Metastable Gel States Using Seeded Self‐Assembly of Low‐Molecular‐Weight Gelators

Here we report on how metastable supramolecular gels can be formed through seeded self‐assembly of multicomponent gelators. Hydrazone‐based gelators decorated with non‐ionic and anionic groups are formed in situ from hydrazide and aldehyde building blocks, and lead through multiple self‐sorting processes to the formation of heterogeneous gels approaching thermodynamic equilibrium. Interestingly, the addition of seeds composing of oligomers of gelators bypasses the self‐sorting processes and accelerates the self‐assembly along a kinetically favored pathway, resulting in homogeneous gels of which the network morphologies and gel stiffness are markedly different from the thermodynamically more stable gel products. Importantly, over time, these metastable homogeneous gel networks are capable of converting into the thermodynamically more stable state. This seeding‐driven formation of out‐of‐equilibrium supramolecular structures is expected to serve as a simple approach towards functional materials with pathway‐dependent properties.     

Combining Modular Ligation and Supramolecular Self‐Assembly for the Construction of Star‐Shaped Macromolecules

A well‐defined random copolymer of styrene (S) and chloromethylstyrene (CMS) featuring lateral chlorine moieties with an alkyne terminal group is prepared (P(S‐co‐CMS), = 5500 Da, PDI = 1.13). The chloromethyl groups are converted into Hamilton wedge (HW) entities (P(S‐co‐HWS), = 6200 Da, PDI = 1.13). The P(S‐co‐HWS) polymer is subsequently ligated with tetrakis(4‐azidophenyl)methane to give HW‐functional star‐shaped macromolecules (P(S‐co‐HWS))₄, = 25 100 Da, PDI = 1.08). Supramolecular star‐shaped copolymers are then prepared via self‐assembly between the HW‐functionalized four‐arm star‐shaped macromolecules ( P(S‐co‐HW )) ₄ and cyanuric acid (CA) end‐functionalized PS (PS–CA, = 3700 Da, PDI = 1.04), CA end‐functionalized poly(methyl methacrylate) (PMMA–CA, = 8500 Da, PDI = 1.13) and CA end‐functionalized polyethylene glycol (PEG–CA, = 1700 Da, PDI = 1.05). The self‐assembly is monitored by ¹H NMR spectroscopy and light scattering analyses.     

A Self‐Growing Strategy for Large‐Scale Crystal Assembly Tubes

Assembled tubular materials have attracted widespread attention due to their potential applications in catalysis, bionics, and optic‐electronics. Many versatile methods, including template assistance and self‐assembly, have been developed for fabrication of tubular materials. Here we demonstrate a self‐growing strategy to prepare large‐scale crystal assembly tubes. Addition of the template and the need for the sophisticated equipment are avoided with this method. The sidewall of the tubes is composed of a layer of polyhedral crystals that are connected together through grain coalescence. We demonstrate that the assembled tubular structure is obtained by the synergetic effect of the passivation layer and the dissolution‐recrystallization process. This facile one‐step strategy and the formation mechanism will offer guidance for fabrication of new superstructures.     

Continuously Tunable Ion Rectification and Conductance in Submicrochannels Stemming from Thermoresponsive Polymer Self‐Assembly

A biomimetic conical submicrochannel (tip side ca. 400 nm) with functions of continuously tunable ion rectification and conductance based on thermoresponsive polymer layer‐by‐layer (LbL) self‐assembly is presented. These self‐assembled polymers with different layers exhibited a capability to regulate the effective channel diameter, and different ion rectifications/conductance were achieved. By controlling temperature, the conformation and wettability of the assembled polymers were reversibly transformed, thus the ion rectification/conductance could be further adjusted subtly. Owing to the synergistic effect, the ion conductance could be tuned over a wide range spanning three orders of magnitude. Moreover, the proposed system can be applied for on‐demand on‐off molecule delivery, which was important for disease therapy. This study opens a new door for regulating channel size according to actual demand and sensing big targets with different size with one channel.