Yali Qiao

Anion-Responsive Metallopolymer Hydrogels for Healthcare Applications

Metallopolymers combine a processable, versatile organic polymeric skeleton with functional metals, providing multiple functions and methodologies in materials science. Taking advantage of cationic cobaltocenium as the key building block, organogels could be simply switched to hydrogels via a highly efficient ion exchange. With the unique ionic complexion ability, cobaltocenium moieties provide a robust soft substrate for recycling antibiotics from water. The essential polyelectrolyte nature offers the metallopolymer hydrogels to kill multidrug resistant bacteria. The multifunctional characteristics of these hydrogels highlight the potential for metallopolymers in the field of healthcare and environmental treatment.

Facile Preparation of Cobaltocenium‐Containing Polyelectrolyte via Click Chemistry and RAFT Polymerization

A facile method to prepare cationic cobaltocenium-containing polyelectrolyte is reported. Cobaltocenium monomer with methacrylate is synthesized by copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between 2-azidoethyl methacrylate and ethynylcobaltocenium hexafluorophosphate. Further controlled polymerization is achieved by reversible addition-fragmentation chain transfer polymerization (RAFT) by using cumyl dithiobenzoate (CDB) as a chain transfer agent. Kinetic study demonstrates the controlled/living process of polymerization. The obtained side-chain cobaltocenium-containing polymer is a metal-containing polyelectrolyte that shows characteristic redox behavior of cobaltocenium.

Terthiophene-Containing Copolymers and Homopolymer Blends as High-Performance Dielectric Materials

This work explores the dielectric and polarization properties of block copolymers and homopolymer blends containing a terthiophene-rich, electronically polarized block (PTTEMA) and an insulating polystyrene block (PS). PTTEMA-b-PS block copolymers were synthesized by reverse addition-fragmentation chain transfer (RAFT) polymerization, and PTTEMA/PS homopolymer blends with the same PTTEMA weight percentages were produced by solution blending. DSC and XRD characterization show that crystallinity increases with PTTEMA content, indicating the presence of terthiophene-rich crystalline domains. Under an applied electric field, these domains are electronically polarized, but the insulating PS block inhibits current leakage, resulting in enhanced dielectric properties. Impedance measurements show that relative permittivity increases with PTTEMA content. The permittivity values are higher in PTTEMA-b-PS copolymers with moderate PTTEMA content due to the ability of the PS block to inhibit PTTEMA association, resulting in a higher density of isolated, terthiophene-rich polarizable domains. Freestanding PTTEMA/PS blend films containing up to 40 wt % PTTEMA have almost 40% greater recoverable energy density compared to pure PS films polarized to the same electric field strength.

Progress in side-chain thiophene-containing polymers: synthesis, properties and applications

In contrast to conventional main-chain conjugated polymers, incorporation of electronically active conjugated oligomers into non-conjugated polymer backbones as pendant groups represents a promising alternative strategy to developing novel electroactive polymer materials that are desirable for potential applications in organic electronics. This review focuses on polymers with thiophene in the side chain and summarizes the most important synthetic approaches to these polymers, including direct controlled polymerization techniques (e.g., ATRP, ROMP, and RAFT) as well as post-polymerization modifications. Additionally, various properties and applications of these polymers are discussed.

Flexible thiophene polymers: a concerted macromolecular architecture for dielectrics

The design of novel dielectric polymers currently employs approaches on capitalizing main-chain and side-chain architectures respectively. This paper reports a concerted macromolecular architecture synergistically tuning both the polymeric backbone and side chain. Our approach relies on an oligomer thiophene side chain and a norbornene backbone. This architecture results in highly flexible and transparent dielectric polymers, superior to methacrylate polymer counterparts. A facile hydrogenation of the polynorbornene backbone results in more than two fold increase in the electric field breakdown strength with the conservation of low dielectric loss.