Clickable Polymerization-Induced Emission Luminogens Toward Color-Tunable Modification of Non-Traditional Intrinsic Luminescent Polymers.

Non-traditional intrinsic luminescent (NTIL) polymer is an emerging field, and its color-tunable modification is highly desirable but still rarely investigated. Here, a click chemistry approach for the color-tunable modifications of NTIL polymers by introducing clickable polymerization-induced emission luminogen (PIEgen), is demonstrated. Through Cu-catalyzed azide-alkyne cycloaddition click chemistry, a series of PIEgens is successful prepared, which is further polymerized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Interestingly, after clickable modification, these monomers are nonemissive in both solution and aggregation states; while, the corresponding polymers exhibit intriguing aggregation-induced emission (AIE) characteristics, confirming their PIEgen characteristics. By varying alkynyl substitutions, color-tunable NTIL polymers are achieved with emission wavelength varying from 448 to 498 nm, revealing a series of PIEgens and verifying the importance of modification of NTIL polymers. Further luminescence energy transfer application is carried out as well. This work therefore designs a series of clickable PIEgens and opens a new avenue for the modification of NTIL polymers via click chemistry, which may cause inspirations to the research fields including luminescent polymer, NTIL, click chemistry, AIE and modification.

Pincushion of Tubule Discovery and Tubular Morphology Landscape Establishment of Block Copolymer Self-Assemblies.

Block copolymer (BCP) self-assembly is a versatile technique in the preparation of polymeric aggregates with varieties of morphologies. However, its morphology library is limited. Here, the discovery of pincushion of tubules is reported for the first time, via BCP self-assembly of poly(4-vinylpyridine)-b-polystyrene (P4VP-b-PS) with very high molecular weight (500 kDa) and asymmetry (2 mol% P4VP). The investigation confirms the importance of core-forming block length on morphology control of BCP self-assemblies, especially with respect to tubular structures. The morphology landscape of tubular structures is successfully established, where dumbbell of tubule, tubule, loose clew of tubules, tight clew of tubules, and pincushion of tubules can be prepared by adjusting the core-forming block length. This work therefore expands the structure library of BCP self-assemblies and opens up a new avenue for the further applications of these tubular materials.

Borinic Acid Polymer: Simplified Synthesis and Enzymatic Biofuel Cell Application.

A simplified one-pot and less harmful method has been introduced for the synthesis of borinic acid monomer. The corresponding borinic acid polymer (PBA) has been prepared by reversible addition-fragmentation chain transfer polymerization. Property investigations confirm the characteristics of PBA as a new type of "smart material" in the field of thermo-responsive polymer. The potential application of PBA in the field of enzymatic biofuel cell has been illustrated with a wide open circuit potential of 0.92 V.

RAFT-Polymerization-Induced Self-Assembly and Reorganizations: Ultrahigh-Molecular-Weight Polymer and Morphology-Tunable Micro-/Nanoparticles in One Pot.

A one-pot method is introduced for the successful synthesis of narrow-distributed (D = 1.22) vinyl polymer with both ultrahigh molecular weight (UHMW) (M w = 1.31 × 106 g mol-1 ) and micro-/nanomorphology under mild conditions. The method involves the following four stages: homogeneous polymerization, polymerization-induced self-assembly (PISA), PISA and reorganization, and PISA and multiple reorganizations. The key points to the production of UHMW polystyrene are to minimize radical termination by segregating radicals in different nanoreactors and to ensure sufficient chain propagation by promoting further reorganizations of these reactors in situ. This method therefore endows polymeric materials with the outstanding properties of both UHMW and tunable micro-/nanoparticles under mild conditions in one pot.

Thermo-responsive behavior of borinic acid polymers: experimental and molecular dynamics studies.

The thermo-responsive properties of borinic acid polymers were investigated by experimental and molecular dynamics simulation studies. The homopolymer poly(styrylphenyl(tri-iso-propylphenyl)borinic acid) (PBA) exhibits an upper critical solution temperature (UCST) in polar organic solvents that is tunable over a wide temperature range by addition of small amounts of H2O. The UCST of a 1 mg mL(-1) PBA solution in DMSO can be adjusted from 20 to 100 °C by varying the H2O content from ∼0-2.5%, in DMF from 0 to 100 °C (∼3-17% H2O content), and in THF from 0 to 60 °C (∼4-19% H2O). The UCST increases almost linearly from the freezing point of the solvent with higher freezing point to the boiling point of the solvent with the lower boiling point. The mechanistic aspects of this process were investigated by molecular dynamics simulations. The latter indicate rapid and strong hydrogen-bond formation between BOH moieties and H2O molecules, which serve as crosslinkers to form an insoluble network. Our results suggest that borinic acid-containing polymers are promising as new "smart" materials, which display thermo-responsive properties that are tunable over a wide temperature range.

A borinic acid polymer with fluoride ion- and thermo-responsive properties that are tunable over a wide temperature range.

A new type of smart borinic acid polymer with luminescence and multiple stimuli-responsive properties is reported. In DMSO with small amounts of water, the homopolymer PBA shows a tunable upper critical solution temperature (UCST). As the amount of water increases from 0 to 2.5 % (v/v), the UCST rises linearly from 20 °C to 100 °C (boiling point of water). Thus, the thermal responsive behavior can be tuned over a wide temperature range. Furthermore, polymer solutions in DMSO show a reversible response to fluoride ions, which can be correlated to the presence of the Lewis acidic borinic acid groups. Upon addition of fluoride, the polymer becomes soluble because the functional R2BOH groups are converted into ionic [R2BF2](-) groups, but turns insoluble again upon addition of H2O, which reverses this process.

One-Pot Synthesis of Stimuli-Responsive Fluorescent Polymers through Polymerization-Induced Emission.

Stimuli-responsive opposite emission (A)/absorption (B) polymer material (A∪B = Ω and A∩B = Ø) represents a novel polymer material that is difficult to prepare. Here, we demonstrate a one-pot strategy for the molecular design of stimuli-responsive opposite emission/absorption polymer material with intriguing properties of opposite emission/absorption and aggregation-induced emission (AIE) type nontraditional intrinsic luminescence (NTIL) in the visible region, through reversible addition-fragmentation chain transfer polymerization-induced emission (PIE) of the N,N-dimethyl-triphenylmethanol moiety. Investigations reveal that NTIL is due to the through-space conjugation effect caused by polymer chain entanglement, when increasing the repeating unit number. The corresponding stimuli-responsive opposite emission/absorption properties are derived from the carbocation-quinoid mechanism, which enables the fluorescence encryption capability. This work therefore demonstrates the proof of concept of a novel opposite emission/absorption polymer material that might cause inspiration in different fields.

Living Covalent-Anionic-Radical Polymerization via a Barbier Strategy.

The developments of the living alkene polymerization method have achieved great progress and enabled the precise synthesis of important polyalkenes with controlled molecular weight, molecular weight distribution, and architecture through an anionic, cationic or radical strategy. However, it is still challenging to develop a living alkene polymerization method through an all-in-one strategy where anionic and radical characteristics are merged into one polymerization species. Here, a versatile living polymerization method is reported by introducing a well-established all-in-one covalent-anionic-radical Barbier strategy into a living polymerization. Through this living covalent-anionic-radical Barbier polymerization (Barbier CARP), narrow distributed polystyrenes, with D as low as 1.05, are successfully prepared under mild conditions with a full monomer conversion by using wide varieties of organohalides, for example, alkyl, benzyl, allyl, and phenyl halides, as initiators with Mg in one pot. This living covalent-anionic-radical polymerization via a Barbier strategy expands the methodology library of polymer chemistry and enables living polymerization with an unconventional polymerization mode.

One-pot synthesis of nanomaterials via RAFT polymerization induced self-assembly and morphology transition.

A simple and facile strategy has been developed for synthesis of nanomaterials via polymerization in high concentration; multiple morphologies can be created and tuned just by variation of the feed ratio and reaction conditions.