Efficient Metal-Free Norbornadiene–Maleimide Click Reaction for the Formation of Molecular Bottlebrushes

Molecular Bottlebrushes as Emerging Nanocarriers: Material Design and Biomedical Application

As a unique unimolecular nanoobject, molecular bottlebrushes (MBBs) have attracted great interest from researchers in nanocarriers attributed to their defined structure, size, and shape. MBBs with various architectures have been proposed and constructed with well-defined domains for loading "cargos", including core, shell, and periphery functional groups. Compared with nanomaterials based on self-assembly, MBBs have lots of advantages, including facile synthesis, flexible compositions, favorable stability, and tunable size and shape, that make them a promising nanoplatform for various applications. This paper summarizes the recent progress during the past decade, with a focus on developments within the last five years in the synthesis of MBBs with different architectures, and uses them as nanocarriers in drug delivery, biological imaging, and other emerging applications.

Tailoring the Architecture of Molecular Bottlebrushes via Click Grafting-Onto Strategy

Molecular bottlebrush (MBB) refer to a synthetic macromolecule, in which a mass of polymeric side chains (SCs) are covalently connected to a macromolecular backbone densely, representing an important type of unimolecular nanomaterial. The chemical composition, size, shape, and surface property of MBB can be precisely tailored by varying the backbones and SCs as well as the grafting density (Gdst ). Meanwhile, the topological structure of backbones and SCs can also significantly affect the chemical and physical properties of MBBs. For the past few years, by combining the structure features of MBB, the polymers with diverse architectures using MBB as building block are synthesized, including linear, branched, and cyclic MBB etc. These promising architectural features will bring MBBs with diverse architectures and lots of applications in advanced materials. For this reason, this work is interested in giving a briefly summary of the recent progress on tailor of well-defined MBBs with diverse architectures using grafting-onto strategy combined with controlled polymerization technique.

Fully physical crosslinked BSA-based conductive hydrogels with high strength and fast self-recovery for human motion and wireless electrocardiogram sensing

The emergence of protein hydrogel sensors has attracted intensive attention because of their biocompatibility and biodegradability, and potential application in wearable electronics. However, natural protein hydrogel sensors commonly exhibited low conductivity, weak mechanical strength, and unsatisfactory self-recovery performance. Herein, a fully physical crosslinked conductive BSA-MA-PPy/P(AM-co-AA)/Fe³⁺ hydrogel based on methacrylic anhydride (MA)-modified and polypyrrole (PPy)-functionalized bovine serum albumin (BSA) introduced into poly(acrylamide-co-acrylic acid) (P(AM-co-AA)) matrix was constructed. Due to the presence of the hydrogen bond complexation and the metal-ligand coordination between ferric ion (Fe³⁺) and the polymer chain, the as-prepared hydrogel showed outstanding mechanical strength (5.36 MPa tensile stress, 17.66 MJ/m³ toughness, and 1.61 MPa elastic modulus) and fast self-recovery performance (99.89 %/96.18 %/93.57 % stress/elastic modulus/dissipated energy within 10 min at room temperature). Meanwhile, the hydrogel exhibited outstanding conductivity (1.13 S/m) due to the presence of PPy and Fe³⁺ moieties, high strain sensitivity (GF = 4.98) and good biocompatibility without causing skin allergic reactions. Thus, the hydrogel can be fabricated into strain sensor to monitor the joint motion of the human body. Moreover, it can be used as soft electrode in electrocardiogram device to realize wireless heart-rate monitoring in the real-time conditions (relaxation and post-exercising), which exhibited excellent reusability, stability, and reliability simultaneously.

The Limited Palette for Photonic Block-Copolymer Materials: A Historical Problem or a Practical Limitation?

Block-copolymer self-assembly has proven to be an effective route for the fabrication of photonic films and, more recently, photonic pigments. However, despite extensive research on this topic over the past two decades, the palette of monomers and polymers employed to produce such structurally colored materials has remained surprisingly limited. In this Scientific Perspective, the commonly used block-copolymer systems reported in the literature are summarized (considering both linear and brush architectures) and their use is rationalized from the point of view of both their historical development and physicochemical constraints. Finally, the current challenges facing the field are discussed and promising new areas of research are highlighted to inspire the community to pursue new directions.

The Limited Palette for Photonic Block-Copolymer Materials: A Historical Problem or a Practical Limitation?

Block-copolymer self-assembly has proven to be an effective route for the fabrication of photonic films and, more recently, photonic pigments. However, despite extensive research on this topic over the past two decades, the palette of monomers and polymers employed to produce such structurally colored materials has remained surprisingly limited. In this Scientific Perspective, the commonly used block-copolymer systems reported in the literature are summarized (considering both linear and brush architectures) and their use is rationalized from the point of view of both their historical development and physicochemical constraints. Finally, the current challenges facing the field are discussed and promising new areas of research are highlighted to inspire the community to pursue new directions.

Synthesis and Visualization of bottlebrush-shaped segmented hyperbranched polymers

Visualization of single molecular morphology provides an intuitive evidence to understand the relationships of molecular structure-synthetic method. Herein, by combining the architectural features of molecular bottlebrush (MBB) and segmented hyperbranched...

Facile synthesis of monocyclic, dumbbell-shaped and jellyfish-like copolymers using a telechelic multisite hexablock copolymer

A heterofunctional hexablock copolymer comprising alternating reactive and non-reactive blocks is designed to generate cyclic, dumbbell-shaped and jellyfish-like copolymers.