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As predicted by Flory–Stockmayer theory, precise control of polymer architecture, molecular weight, and molecular weight distribution in the polymerization of tri-vinyl monomers has been recognized as a considerable challenge in polymer chemistry. Multi-responsive polymers are generally designed by incorporating multiple sensitive moieties together in one polymer chain. However, this strategy suffers from issues of complicated synthesis and the compatibilities of these functional moieties. The design of multi-responsive polymers by incorporating only one sensitive moiety is of considerable importance. Here, we report the successful, well-controlled polymerization of tri-vinyl containing dynamic covalent boroxine (DCB) monomer, and utilization of DCB as a side-chain building block in the molecular design of a multi-responsive polymer. Benefiting from dynamic characteristics, the DCB-incorporated polymer exhibits tunable penta-responsive behavior leading to response/sensing of water, fluoride ion, and acid and base, as well as lower critical solution temperature-type thermo-responsive properties, which cover a wide temperature range, and with both solution–colloid transition and sol–gel transition observed. The utilization of only one DCB moiety in the design of the tunable penta-responsive polymer breaks the stimulus record of multi-responsive polymers, and opens up a new avenue in the molecular design and application of functional polymer materials.

Summary Monofunctional carbonyls are readily available from fossil fuels and biomass on earth. They are cornerstones of organic chemistry but are rarely used as monomers for polymer materials. Here, we demonstrate a versatile single-atom polymerization (SAP) method using monofunctional carbonyls as building blocks, where bifunctionalization of monofunctional carbonyls is critical. Through SAP, a series of alcohol-containing polymers, which are difficult to synthesize by other traditional polymerization methodologies, are prepared. These polymers exhibit structure-specific luminescence, and polytriphenylethanol represents a rare type of aggregation-induced emission luminogen without traditional chromophores. This can be used for supersensitive explosive detection at the picogram level. SAP also results in polymerization-induced emission behavior from nonemissive monomers. Due to the cornerstone significance and extreme availability of carbonyls and unique polymer functionalities, this may allow us to exploit earth’s carbonyl resources more efficiently.

Summary Carbon-carbon bond formation through polarity reversal ketyl radical anion coupling of carbonyls has inspired new reaction modes to this cornerstone carbonyl group and played significant roles in organic chemistry. The introduction of this resplendent polarity reversal ketyl strategy into polymer chemistry will inspire new polymerization mode with unpredicted discoveries. Here we show the successful introduction of polarity reversal ketyl approach to polymer chemistry to realize self-condensing ketyl polymerization with polymerization-induced emission. In this polarity reversal approach, it exhibits intriguing reversed polymerizability, where traditional excellent leaving groups are not suitable for polymerization but challenging polymerizations involving the cleavage of challenging C-F and C-CF3 bonds are realized under mild Barbier conditions. This polarity reversal approach enables the polymer chemistry with polarity reversal ketyl mode, opens up a new avenue toward the polymerization of challenging C-X bonds under mild conditions, and sparks design inspiration of new reaction, polymerization, and functional polymer., Graphical Abstract, Highlights • Self-condensing ketyl polymerization • Polymerization-induced emission • C-F/C-CF3 activation polymerization • Polarity reversal and reversed polymerizability, Organic Chemistry; Optical Property; Polymers

The pH-induced demulsification behaviors of “on-off” oil-in-water emulsions using cetyltrimethylammonium bromide (CTAB) and potassium phthalic acid (PPA) mixtures as emulsifiers were investigated by coarse-grained (CG) molecular dynamics (MD) simulations and experiments, aiming to design a new pH-responsive emulsion. On the one hand, we simulated the stability of emulsions of n -octane and aqueous CTAB/PPA solution, and phase diagrams of emulsion with different CTAB/PPA contents were observed at different pH. Furthermore, the demulsification processes from the low pH to high pH was investagated and clearly it began with film rupture and then accomplished with droplets fusion in few nanoseconds. Via analyzing the structure and molecular arrangment of the emulsion droplets, it was found that the reasons on pH-induced demulsification were weak hindrance effect of the surfactant film and electrostatic repulsion among emulsion droplets at high pH. On the other hand, through our experiments, the differences on stability of emulsions were verified and the reversible emulsification and demulsification processes by changing pH values were observed, which agreed well with our simulations. This work designed a new kind of pH-responsive emulsion using commercial surfactants CTAB/PPA by simulations and verified its pH-induced demulsification by experiments. It sets up a bridge between CG MD approach and experiment, which is expected to trigger further understanding and studies on stimuli responsive emulsion systems.

Electron-deficient borinic acid monomers and corresponding polymers were synthesized with different substituents via a one-pot reaction of Grignard reagents with trimethoxyborane and reversible addition–fragmentation chain transfer polymerization, respectively. Further investigations of substituent effects of borinic acid polymers (PBAs) were carried out, indicating that the thermoresponsive properties of PBAs benefit from the increase of steric hindrance of PBA substituent, while the binding affinity of PBAs with Alizarin Red S, 8-hydroxyquinoline (HQ), and fluoride ion decreases with the increase of steric hindrance of substituent. Attributed to the strong dative N → B bond and the strongly luminescent boron quinolate, the application of phenyl PBA for fluorescence detection of HQ is realized with high sensitivity at the ppm level. These results therefore confirm that borinic acid-containing polymer is a new type of stimuli-responsive polymer in the field of thermoresponsiveness over a wide temperature ...

Luminescent polymers are generally constructed through polymerization of luminescent moieties. Polymerization itself, however, is mainly used for constructing polymer main chain, and the importance of polymerization on luminescence has yet to be explored. Here, we demonstrate a polymerization-induced emission strategy producing luminescent polymers by introducing Barbier reaction to hyperbranching polymerization, which allows luminescent properties to be easily tuned from the traditional type to an aggregation-induced emission type by simply adjusting the monomer structure and the polymerization time. When rotation about the phenyl groups in hyperbranched polytriphenylmethanols (HPTPMs) is hindered, HPTPMs exhibit traditional emission property. When all phenyl groups of HPTPM are rotatable, i.e., p,p',p″-HPTPM, it exhibits interesting aggregation-induced emission property with tunable emission colors from blue to yellow, by just adjusting polymerization time. Further applications of aggregation-induced emission type luminescent polymers are illustrated by the facile fabrication of white light-emitting diode (LED) and light-harvesting film with an antenna effect >14. This Barbier hyperbranching polymerization-induced emission provides a new strategy for the design of luminescent polymers and expands the methodology and functionality library of both hyperbranching polymerization and luminescent polymers.

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.

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.