Multiple morphologies from a novel diblock copolymer containing dendronized polymethacrylate and linear poly(ethylene oxide)

Polymeric Bowl-Shaped Nanoparticles: Hollow Structures with a Large Opening on the Surface

Polymeric bowl-shaped nanoparticles (BNPs) are anisotropic hollow structures with large openings on the surface, which have shown advantages such as high specific area and efficient encapsulation, delivery and release of large-sized cargoes on demand compared to solid nanoparticles or closed hollow structures. Several strategies have been developed to prepare BNPs based on either template or template-free methods. For instance, despite the widely used self-assembly strategy, alternative methods including emulsion polymerization, swelling and freeze-drying of polymeric spheres, and template-assisted approaches have also been developed. It is attractive but still challenging to fabricate BNPs due to their unique structural features. However, there is still no comprehensive summary of BNPs up to now, which significantly hinders the further development of this field. In this review, the recent progress of BNPs will be highlighted from the perspectives of design strategies, preparation methods, formation mechanisms, and emerging applications. Moreover, the future perspectives of BNPs will also be proposed.

Novel Amphiphilic Dendronized Copolymers Formed by Enzyme-Mediated "Green" Polymerization

This study reports the first enzyme-mediated polymerization of dendritic macromonomers. The enzyme substrates are prepared by "click" conjugation between tyrosine and hydrophilic triethylene glycol (TrEG)-based dendrons of three generations (G1, G2, and G3). The resulting enzyme-polymerizable dendrons are defect-free as revealed by mass spectrometry, size-exclusion chromatography, and spectroscopic techniques. The phenol-containing macromonomers are water soluble and their polymerizations into dendronized polymers (denpols) are catalyzed by laccase (an oxidoreductase) under benign conditions (45 °C and aqueous medium at pH = 4.0) with copolymer yields between 30 and 40%. The resulting denpols consist of unnatural poly(tyrosine) backbones and dendritic poly(ether-ester) side chains and have molecular masses up to ∼13 000 Da (generation 1), ∼20 000 Da (generation 2), and ∼36 000 Da (generation 3) determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) analyses. They display amphiphilic properties and self-assemble in aqueous solutions to form aggregates with generation-dependent morphologies.

The generation of polymeric nano-bowls through 3D confined assembly and disassembly

Here we present a facile yet robust strategy to prepare polymer nano-bowls through 3D confined assembly and disassembly of block copolymers. Unlike the previously reported methods, this strategy allows for generation of nano-bowls with precisely controllable opening degree and thickness. Typically, polystyrene-b-poly(4-vinyl pyridine) (PS-b-P4VP) nano-bowls can be generated through confined assembly of PS-b-P4VP with homopolystyrene (hPS) to form Janus particles, followed by the crosslinking of P4VP domains and disassembly of PS domains. The opening degree of the nano-bowls can be precisely controlled by the weight fraction of hPS, and the thickness can be tailored by the varying molecular weight of PS-b-P4VP. By selectively loading gold nanoparticles in P4VP domains, it is anticipated that the resulting hybrid nano-bowls would be useful for surface enhanced Raman scattering and potential catalytic reaction applications.

Dendronized supramolecular polymers

Supramolecular polymers from dendritic motifs combine the dynamic nature of supramolecular construction and inherent features from covalent dendronized polymers.