Dendritic Solid Polymer Electrolytes: A New Paradigm for High-Performance Lithium-Based Batteries

Li-ions battery is widely used and recognized, but its energy density based on organic electrolytes has approached the theoretical upper limit, while the use of organic electrolytes also brings some safety hazards (leakage and flammability). Polymer electrolytes (PEs) are expected to fundamentally solve the safety problem and improve energy density. Therefore, Li-ions battery based on solid PE has become a research hotspot in recent years. However, low ionic conductivity and poor mechanical properties, as well as a narrow electrochemical window limit its further development. Dendritic PEs with unique topology structure has low crystallinity, high segmental mobility, and reduced chain entanglement, providing a new avenue for designing high-performance PEs. In this review, the basic concept and synthetic chemistry of dendritic polymers are first introduced. Then, this story will turn to how to balance the mechanical properties, ionic conductivity, and electrochemical stability of dendritic PEs from synthetic chemistry. In addition, accomplishments on dendritic PEs based on different synthesis strategies and recent advances in battery applications are summarized and discussed. Subsequently, the ionic transport mechanism and interfacial interaction are deeply analyzed. In the end, the challenges and prospects are outlined to promote further development in this booming field.

Sunlight-Mediated Thiol-Ene/Yne Click Reaction: Synthesis and DNA Transfection Efficiency of New Cationic Lipids

The design of green synthetic reaction conditions is very challenging, especially for biomaterials, but worthwhile if the compounds can be easily synthesized in the aqueous medium. Herein, we report the development of sunlight-mediated thiol-ene/yne click reaction in the presence of a catalytic amount of tert-butyl hydroperoxide (TBHP) in an aqueous medium. The optimized reaction conditions were successfully applied to synthesize a series of small molecules and lipids in a single step in the aqueous medium. The synthetic cationic lipid/co-lipid formed positively charged stable nanosized liposomes that effectually bind with the genetic materials. The in vitro DNA transfection and cellular uptake assays showed that the synthesized cationic lipids have comparable efficiency to commercially available Lipofectamine 2000. This mild synthetic strategy can also be used for smart design of novel or improvement of prevailing lipid-based nonviral gene delivery systems. Such chemical transformations in the aqueous medium are more environment-friendly than other reported thiol-ene/yne click reactions performed in an organic solvent medium.

Hyperbranched polydisulfides

Synthesis, aqueous aggregation, hydrophobic guest encapsulation, non-covalent encapsulation stability and glutathione responsive degradation of amphiphilic hyperbranched polydisulfides have been reported.

Recent Advances on Reactive Oxygen Species-Responsive Delivery and Diagnosis System

Reactive oxygen species (ROS) play crucial roles in biological metabolism and intercellular signaling. However, ROS level is dramatically elevated due to abnormal metabolism during multiple pathologies, including neurodegenerative diseases, diabetes, cancer, and premature aging. By taking advantage of the discrepancy of ROS levels between normal and diseased tissues, a variety of ROS-sensitive moieties or linkers have been developed to design ROS-responsive systems for the site-specific delivery of drugs and genes. In this review, we summarized the ROS-responsive chemical structures, mechanisms, and delivery systems, focusing on their current advances for precise drug/gene delivery. In particular, ROS-responsive nanocarriers, prodrugs, and supramolecular hydrogels are summarized in terms of their application for drug/gene delivery, and common strategies to elevate or diminish cellular ROS concentrations, as well as the recent development of ROS-related imaging probes were also discussed.

Thiol-yne Click Polymerization

Thiol-yne click polymerization (TYCP) is one of the most significant synthetic techniques for artificial polymers, due to its simplicity, efficiency, and functionality tolerance. In nature, it is a classic nucleophilic addition reaction and a step-growth polymerization, which can be initiated or accelerated in the presence of free-radicals, amines, and transition metals, respectively. Its rate is greatly influenced by the structures (i.e., their electrophilicity and steric hindrance) of the used thiols and/or alkynes. With aliphatic monomers being used as feeding materials, the topological architectures (such as linear, branching, and cross-linked network, etc.) and available functional groups (such as hydroxyl, carboxyl, amino, and epoxy groups, and so on) can be facilely tailored via altering the chemical structure and feeding order. In contrast, for aromatic monomers, mono-addition occurs only during the process of thiol-yne click reaction, leading exclusively to linear poly(vinyl thioether)s. These sulfur-containing polymers synthesized by TYCP are promising to be widely utilized as high refractive index materials, photovoltaic materials, drug-delivery vehicles, biomaterials, and hybrid materials, etc.

Superbase catalyzed regio-selective polyhydroalkoxylation of alkynes: a facile route towards functional poly(vinyl ether)s

A superbase of t-BuP₄ catalysed polyhydroxylation of aromatic diynes was established, and regio-regular poly(vinyl ether)s with versatile properties were produced.

One-pot approach to synthesize hyperbranched poly(thiol–ether amine) (hPtEA) through sequential “thiol–ene” and “epoxy–amine” click reactions

We demonstrated a one-pot approach to synthesize hyperbranched poly(thiol–ether amine) (hPtEA) through sequential “thiol–ene” and “epoxy–amine” click reactions, both of which were well traced using in situ¹H-NMR spectra.

Novel triethylamine catalyzed S → O acetyl migration reaction to generate candidate thiols for construction of topological and functional sulfur-containing polymers

Various sulphur-containing monomers and polymer materials transformed from different epoxy compounds.

The electrophilic effect of thiol groups on thiol–yne thermal click polymerization for hyperbranched polythioether

The significant effect of the electrophilicity of the thiol groups on thiol–yne click polymerization was found and well demonstrated.

Hyperbranched polymers: advances from synthesis to applications

This review summarizes the advances in hyperbranched polymers from the viewpoint of structure, click synthesis and functionalization towards their applications in the last decade.

Synthesis of hyperbranched polymers and their applications in analytical chemistry

This review focuses primarily on the recent developments in the synthesis of hyperbranched polymers and their application in analytical chemistry.

Sequentially hetero-functional, topological polymers by step-growth thiol-yne approach

Sequence-controlled polymers (SCPs) such as DNA and proteins play an important role in biology. Many efforts have been devoted to synthesize SCPs in the past half a century. However, to our knowledge, the artificial sequences containing independently functional groups have never been reported. Here, we present a facile and scalable approach based on radical-initiated step-growth polymerization to synthesize sequence-controlled functional polymers (SCFPs) with various topologies, covering from linear to random and hyperbranched polymers. The functional groups, such as OH/NH2, OH/COOH, and NH2/N3, alternately arranged along the chain, which were further selectively functionalized to achieve DNA-mimic and hetero-multifunctional SCPs. This user-friendly strategy exhibits advantages of commercially available monomers, catalyst-free process, fast reaction, high yield and water solvent, opening a general approach to facile and scalable synthesis of SCFPs.

High refractive index polyvinylsulfide materials prepared by selective radical mono-addition thiol–yne chemistry

Linear and hyperbranched polyvinylsulfides with a high refractive index (n_D = 1.68–1.76) have been synthesized by selective mono-addition thiol–yne chemistry employing dithiols and di- and trialkynes.

Enhanced drug toxicity by conjugation of platinum drugs to polymers with guanidine containing zwitterionic functional groups that mimic cell-penetrating peptides

Inspired by the Ringsdorf model, statistical copolymers with solubility enhancers, platinum drugs and groove binders were compared.

Growing hyperbranched polymers using natural sunlight

In nature, a sapling can grow into a big tree under irradiation of sunlight. In chemistry, a similar concept that a small molecule only exposing to sunlight grows into a hyperbranched macromolecule has not been realized by now. The achievement of the concept will be fascinating and valuable for polymer synthesis wherein sunlight is inexpensive, abundant, renewable, and nonpolluting. Herein, we report a new strategy in which small monomers can directly grow into big hyperbranched macromolecule under irradiation of sunlight without any catalyst.

Facile functionalization of polyesters through thiol-yne chemistry for the design of degradable, cell-penetrating and gene delivery dual-functional agents

Synthesis of polyesters bearing pendant amine groups with controlled molecular weights and narrow molecular weight distributions was achieved through ring-opening polymerization of 5-(4-(prop-2-yn-1-yloxy)benzyl)-1,3-dioxolane-2,4-dione, an O-carboxyanhydride derived from tyrosine, followed by thiol-yne "click" photochemistry with 2-aminoethanethiol hydrochloride. This class of biodegradable polymers displayed excellent cell penetration and gene delivery properties with low toxicities.