Sequence structure controllable polymerization-induced self-assembly

Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating biosynthesis.However,the reported PISA formulations primarily focus on developing nano-objects with new chemical compositions and rarely on structural regulation of polymers with specific components.Herein,sequence structure controllable polymerization-induced self-assembly(SCPISA)is reported by using 7-(2-methacryloyloxyethoxy)-4-methylcoumarin(CMA)as a monomer.During the copolymerization of 2-hydroxyethyl methacrylate(HEMA)and CMA,controlled incorporation of CMA units into the polymer chains can be realized by programmable light/heat changes.SCPISA-based P(HEMA-co-CMA)copolymers with the same composition but different sequence structures generate a range of assemblies.Moreover,the morphologies of the resultant nano-objects can also be controlled by regulating the feed molar ratio of CMA and HEMA,which is similar to the conventional PISA,but the synthesis procedure is obviously simplified in SCPISA.The versatility of the methodology is further demonstrated by the fabrication of different functional nano-objects with sequence structure-dependent morphologies in SCPISA systems with different functional monomers.

Diamines,CS2 and Monoisocyanide-participated Polymerizations for Large-scale Synthesis of Polythioureas and Thioformamide

Multicomponent polymerizations(MCPs)are powerful tools to synthesize functional polymers with great structural diversity,low cost and high efficiency,which usually generate single polymer product.Herein,a robust one-pot diamines,CS_(2)and monoisocyanide-participated catalyst-free polymerization was developed at room temperature to produce polythiourea and thioformamide simultaneously in equal equivalent,which was featured with cheap monomers,simple operation and mild condition,affording various polythioureas with high Mws of up to 4.75×10^(4)g/mol in high yields of up to 98%.Polythioureas with varied chain composition and sequence-controlled structure could be synthesized in 62 g-scale from copolymerization or multicomponent tandem polymerization,enabling facile tuning of thermal property,crystallinity,mechanical property,and fluorescence.The abundant irregular hydrogen bonds endowed the polythioureas excellent glassy state self-healing property at room temperature or below 0℃.This polymerization provided an efficient and economic approach to access functional polythioureas.

Research progress in the living/controlled polymerization of(meth)acrylate monomers by Lewis pair

Lewis pair polymerization(LPP)has demonstrated its unique advantages,such as high activity,high stability,and adjustable variability,towards the polymerization of(meth)acrylate monomers in comparison with the other polymerization techniques.The combination of Lewis acid(LA)and Lewis base(LB)to construct Lewis pairs(LPs)with appropriate Lewis basicity,Lewis acidity,and steric effects would significantly impact the polymerization process,including chain initiation,propagation,termination and chain transfer reaction,as well as polymerization manner of monomers.In this feature article,we briefly review recent progress made by our research group towards the living/controlled polymerization of(meth)acrylate monomers,which were accomplished by a series of newly designed LPs,including monofunctional LPs,dual-initiating LPs and intramolecular tethered trifunctional LP.This article is divided into three parts:(1)the development of monofunctional living/controlled LP polymerization system;(2)the design and preparation of dual-initiating LPs in synthesizing thermoplastic elastomers;(3)the application of intramolecular trifunctional LP to the synthesis of cyclic polymers.These developed LPPs have demonstrated their powerful capability in precise control over the molecular weight,molecular weight distribution,and monomer sequence as well as the topology of polymers.This review will serve as a good resource or guideline for researchers currently working in the area of LPP and for those who are interested in synthesizing new materials by LPP.

Informational Polymers with Precise Carbamate Sequences

Sequence-defined oligocarbamates were synthesized by orthogonal iterative chemistry on a modified Wang solid support.In this approach,amino alcohol building blocks,containing either primary or secondary amines,were used in order to obtain ondemand either a classical urethane motif−NH−CO−O−or a Nsubstituted urethane linkage−NR−CO−O−.Hence,aperiodic carbamate sequences could be easily prepared in this work.Polymers with different monomer sequences and chain-length were synthesized.Characterization by NMR,SEC and ESI-MS indicated formation of near-monodisperse polymers.Furthermore,these informational oligocarbamates were sequenced by MS/MS.Very interestingly,it was found that a fully orthogonal fragmentation of−NH−CO−O−urethane motifs occurs in these macromolecules.

Modular Synthesis of Tetraurea and Octaurea Macrocycles Encoded with Specific Monomer Sequences

Intermolecular hydrogen bonding among urea units grants prominent mechanical strength to polyurea elastomer materials.However,such interactions can cause significant solubility problems when synthesizing oligourea macrocycles with a large number of urea units,and it remains unknown for macrocycles containing more than six urea units.Here,we demonstrate a two-step,modular strategy for making a new class of tetraurea and octaurea macrocycles using commercially available building blocks.Intramolecular hydrogen bonding within the fundamental o-phenylene bis(urea)unit is the key to overcoming intermolecular hydrogen bonding to form favorable conformations for ring-closure reactions.The size and monomer sequences can be controlled by varying the flexibility of the spacers.Rigid diphenyl methylene and diphenyl ether linkers selectively afford tetraurea macrocycles,whereas the flexible hexylene linker produces octaurea macrocycles.Macrocycles encoded with two different spacers were also made.All these macrocycles are confirmed by X-ray diffraction structural analysis of the complexed forms with sulfate anions.Interestingly,a unique“figure-eight”structure is observed for the complex of MUH octaurea macrocycle with two encapsulated sulfate anions.Our study shows a paradigm of making large oligourea macrocycles with designer properties in a programable manner with tunable monomer sequences.