Growing hyperbranched polymers using natural sunlight

Thiolactone chemistry, a versatile platform for macromolecular engineering

This review covers the extensive use of γ-thiolactone chemistry as a versatile and powerful tool for macromolecular engineering and the preparation of various polymer architectures, such as functional, alternating, or sequence-controlled (co)polymers.

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.

Enantioselective cytotoxicity of chiral polymer vesicles with linear and hyperbranched structures

Herein, we study the enantioselective cytotoxicity of vesicles self-assembled by optically active linear polymers (LNPs) and hyperbranched polymers (HBPs). Compared to HBP vesicles, LNP vesicles exhibit properties such as a higher surface charge density and more violent interaction with simulated biomembranes which results in larger cytotoxicity against HeLa cells. Specifically, racemic-LNP vesicles exhibit the largest cytotoxicity of all. More interestingly, there is no significant enantioselective dependence of HBP vesicles on the abovementioned properties. Overall, we proved that the cytotoxicity of vesicles is deeply related to chirality and topological-structures. This research is of great fundamental value for the design of novel bio-interface materials.

A sequential native chemical ligation – thiol-Michael addition strategy for polymer–polymer ligation

Native Chemical Ligation (NCL) between cysteine-terminated polymers and functional thioesters has been employed to prepare functional (co)polymers. The retained thiol functionality at the NCL junction can be exploited for thiol-Michael addition.

Effect of Selected Thiols on Cross-Linking of Acrylated Epoxidized Soybean Oil and Properties of Resulting Polymers

The effect of the chemical structure and functionality of three structurally different thiols on the cross-linking of acrylated epoxidized soybean oil and on the properties of the resulting polymers was investigated in this study. 1,3-Benzenedithiol, pentaerythritol tetra(3-mercaptopropionate), and an hexathiol synthesized from squalene were used in the cross-linking of acrylated epoxidized soybean oil by thiol⁻Michael addition reaction. The reactivity of thiols determined from calorimetric curves followed the order: 1,3-benzenedithiol > pentaerythritol tetra(3-mercaptopropionate) > hexathiolated squalene. Thermal and mechanical properties and the swelling in different solvents of the cross-linked polymers were studied. The cross-linked polymer obtained from 1,3-benzenedithiol showed the highest swelling values in chloroform and toluene. The cross-linked polymer with pentaerythritol tetra(3-mercaptopropionate) fragments showed the best mechanical performance (highest mechanical strength and Young's modulus) and thermal stability. The cross-linked polymers from hexathiolated squalene showed the highest glass transition temperature.

Dendrite Suppression by Synergistic Combination of Solid Polymer Electrolyte Crosslinked with Natural Terpenes and Lithium-Powder Anode for Lithium-Metal Batteries

Lithium-metal anode has fundamental problems concerning formation and growth of lithium dendrites, which prevents practical applications of next generation of high-capacity lithium-metal batteries. The synergistic combination of solid polymer electrolyte (SPE) crosslinked with naturally occurring terpenes and lithium-powder anode is promising solution to resolve the dendrite issues by substituting conventional liquid electrolyte/separator and lithium-foil anode system. A series of SPEs based on polysiloxane crosslinked with natural terpenes are prepared by facile thiol-ene click reaction under mild condition and the structural effect of terpene crosslinkers on electrochemical properties is studied. Lithium powder with large surface area is prepared by droplet emulsion technique (DET) and used as anode material. The effect of the physical state of electrolyte (solid/liquid) and morphology of lithium-metal anode (powder/foil) on dendrite growth behavior is systematically studied. The synergistic combination of SPE and lithium-powder anode suggests an effective solution to suppress the dendrite growth owing to the formation of a stable solid-electrolyte interface (SEI) layer and delocalized current density.

Precisely Alternating Functionalized Polyampholytes Prepared in a Single Pot from Sustainable Thiolactone Building Blocks

Polyampholytes with precisely alternating cationic and anionic functional groups were prepared using sustainable thiolactone building blocks in a simple one-pot procedure at room temperature and in water. Ring opening of the N-maleamic acid-functionalized homocysteine thiolactone monomer enabled the introduction of different functional groups into the polymer chain, which contributed to both ionic and hydrogen bonding interactions. The resulting polyampholytes exhibited various isoelectric points while maintaining high solubility in water under different pH and ionic strengths, which expands their potential applications. Finally, it is shown that the upper critical solution temperature (UCST) of these alternating polyampholytes in water/ethanol (30/70% vol) solutions can be tuned as a function of the content of ionic and hydroxyl groups.

Poly(acrylamide-homocysteine thiolactone) as a synthetic platform for the preparation of polymeric ionic liquids by post ring-opening-orthogonal modifications

Post-modification of Poly(Acrylamide-Homocysteine Thiolactone) provides a variety of advanced polymeric materials with different morphologies and structural diversity.

Asymmetric Michael addition in an aqueous environment with the assistance of optically active hyperbranched polymers

A novel optically active hyperbranched polymer can serve as the chiral scaffolds to promote asymmetric Michael addition reaction in an aqueous environment with a high product yield and enantioselectivity.

Circularly polarized light triggered enantioselective thiol–ene polymerization reaction

Herein, circularly polarized light is utilized to trigger an enantioselective polymerization reaction, resulting in the synthesis of an optically active polymer from racemic monomers in the absence of any chiral dopant or catalyst.

Facile synthesis of thermo-, pH-, CO2- and oxidation-responsive poly(amido thioether)s with tunable LCST and UCST behaviors

Multi-responsive N-substituted poly(amido thioether) copolymers synthesized by one-pot amine–thiol–acrylate polyaddition could exhibit composition-dependent and stimuli-triggered single or double thermoresponsivity.

One-pot sequential multicomponent reaction and a multicomponent polymerization method for the synthesis of topologically different polymers

The synthesis of topologically different polymers via a one-pot sequential multicomponent reaction and multicomponent polymerization is reported.

Sequential Michael addition thiol–ene and radical-mediated thiol–ene reactions in one-pot produced sequence-ordered polymers

Sequential Michael addition-based thiol–ene and free radical mediated thiol–ene reactions for preparing sequence-ordered polymers are reported for the first time.

Synthesis and self-assembly behavior of POSS-embedded hyperbranched polymers

We demonstrate a simple approach to prepare POSS-embedded hyperbranched amphiphiles, presenting morphological transition from micelle to vesicle in aqueous solution.

Poly(thiolactone) homo- and copolymers from maleimide thiolactone: synthesis and functionalization

We describe the synthesis of a thiolactone-functionalized maleimide (MITla), its copolymerization into poly(thiolactone) homo- and copolymers via controlled or free radical polymerization (CRP or FRP) techniques, and subsequent modification.