Latent Monomer Research Articles

Tailoring Hydrogen-Bonding Strategy for Sequence-Dependent and Thermo/pH Dual-Responsive Clusteroluminescence.

Rational design of monomer sequence for desired properties is challenging. This study investigates the effect of monomer distribution of double hydrophilic copolymers (DHCs) with electron-rich units on cluster triggered emission (CTE) capacity. By means of combining latent monomer strategy, reversible addition fragmentation chain transfer (RAFT) polymerization and selective hydrolysis technology, the random, pseudo di-block and the gradient DHCs consisting of pH-responsive polyacrylic acid (PAA) segments and thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) segments were successfully synthesized in a controlled manner. Moreover, the gradient DHCs showed a tremendously increased luminescent intensity due to the distinct hydrogen-bonding interaction compared to random and pseudo di-block DHCs. To the best of our knowledge, this is the first reported the direct correlation between luminescent intensity and sequence structure of non-conjugated polymer. Meanwhile, thermo and pH dual-responsive clusteroluminescence could be easily performed. This work demonstrates a novel and facile method to tailor the hydrogen-bonding for the stimuli-responsive light-emitting polymers.

Maleimide Chemistry: Enabling the Precision Polymer Synthesis

AbstractHerein is presented a compilation of the main characteristics of maleimide chemistry in developing the precisely controlled polymers, including the design of sequence‐controlled polymers, topological polymers, and polymeric single‐chain nanoparticles. The synthetic methods, relied on the versatilities of the maleimide moieties as a latent monomer which leads to an efficient alternative in various innovative applications, especially in self‐healing material, self‐reporting materials for real‐time monitoring, and also in data storage and anticounterfeiting technologies. The core of the content in this review is focused on the up‐to‐data advances and publications on the major of maleimide chemistry in our research group. What is the most favorite and original chemistry developed in your research group?Maleimide chemistry in precision polymer synthesis.How do you get into this specific field? Could you please share some experiences with our readers?When I was a junior high school student, the chemistry attracted me very much. Chemistry is an extraordinary magic, which virtually generates molecules, basic units and everything on earth. I selected the polymer chemistry area when I pursuit my MSc and PhD in Soochow University. The polymer chemistry is the basic and originality of polymer science, which has created tremendous useful materials and greatly benefited humanity in the past century. Engaging in chemistry research is tedious and hard most of the time, but I like the joy and accomplishment at the moment when the experiment succeeds. It's like tea tasting, thekind of fleeting back sweetness makes me yearn and intoxicated.How do you supervise your students?I always encourage students to believe themselves, however don't always believe what others have said. The students should have their own judgments based on broad literature survey, comprehensive learning and deep thinking. The students should not take the publications but the improvements of research capability as the only target when pursuing the academic degree.What is the most important personality for scientific research?Be joyful, enthusiastic, persistent and careful.How do you keep balance between research and family?I like cooking for my family. Cooking is similar with chemical experiments. I think that cooking is a good balance between research and family.

The conformational stability of pro-apoptotic BAX is dictated by discrete residues of the protein core

BAX is a pro-apoptotic member of the BCL-2 family, which regulates the balance between cellular life and death. During homeostasis, BAX predominantly resides in the cytosol as a latent monomer but, in response to stress, transforms into an oligomeric protein that permeabilizes the mitochondria, leading to apoptosis. Because renegade BAX activation poses a grave risk to the cell, the architecture of BAX must ensure monomeric stability yet enable conformational change upon stress signaling. The specific structural features that afford both stability and dynamic flexibility remain ill-defined and represent a critical control point of BAX regulation. We identify a nexus of interactions involving four residues of the BAX core α5 helix that are individually essential to maintaining the structure and latency of monomeric BAX and are collectively required for dimeric assembly. The dual yet distinct roles of these residues reveals the intricacy of BAX conformational regulation and opportunities for therapeutic modulation.

Bridging from the Sequence to Architecture: Graft Copolymers Engineering via Successive Latent Monomer and Grafting‐from Strategies†

Main observation and conclusionThe on‐demand building copolymer structures, from sequence to architecture, is crucial in understanding the relation between polymer structure and property, meanwhile motivating the innovation of polymer hierarchy. However, the challenge is conspicuous for complicated polymer structures from inherently intricate polymerization. In this work, copolymers with tailored grafting density and distributions were achieved using successive latent monomer and grafting‐from strategies. The hydroxyl group functionalized furan/maleimide adduct (FMOH) was selected as the latent monomer for RAFT polymerization of an array of copolymers with tailored localization of hydroxyl group along the main chain. The hydroxyl group further initiated the ring opening polymerization (ROP) of L‐lactide or ε‐caprolactone, resulting in a library of multicomponent copolymers via grafting‐from strategy. The initiating efficiency reached to ~100% with variable molecular weight (21300—58600 Da) and narrow distributions (ÐM < 1.25), indicating that such graft copolymers possessed controlled density and distribution of side chains as its linear template. The investigation on thermal properties of the well‐defined graft copolymers implied that the precise tailoring over copolymer structures at the molecule level could lead to tunable chemical/physical properties. This work bridged polymer from sequence to architecture, unveiled a new method in creating graft copolymers with programmable structures and provided the insight into the structure/property relationship.

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This work describes the constructions of graft copolymers with controlled density and distribution of side chains by successive latent monomer and grafting‐from strategies. More details are discussed in the article by Zhang et al. on page 1273—1280.image

2,5-Dimethylfuran/Acrylonitrile as Latent Monomer for Sequence-Controlled Copolymer and Sequence-Dependent Thermo-Responsivity.

Sequence control has attracted increasing attention for its ability of regulating polymer property and performance. Herein, the sequence-controlled polymer containing acrylonitrile (AN) is achieved by using 2,5-dimethylfuran/acrylonitrile adduct as a latent monomer. The temperature-dependent retro Diels-Alder reaction is engaged in controlling the release of AN during RAFT polymerization, that is, regulating the instant AN concentration via a non-invasive and in situ manner. Such control over the instant AN concentration and particularly the molar ratio of comonomer pair leads to the simultaneous change of monomer units in "living" polymeric chain, thus resulting in the sequence-controlled polymeric structures. By delicately manipulating the polymerization temperature, diverse sequence-on-demand structures of AN-containing copolymers, such as poly(AN/methyl methacrylate), poly(AN/styrene), poly(AN/butyl acrylate), poly(AN/N,N-dimethylacrylamide), and poly(AN/N-isopropylacrylamide) are created. Meanwhile, this study presents an initial attempt in tuning the thermal responsivity of poly(AN/N-isopropylacrylamide), which is closely correlated to the sequence of polymer structure. More importantly, the polymer with averagely distributed AN units results in the higher thermal sensitivity. Therefore, the synthetic strategy proposed in this work offers a promising platform for accessing the sequence-controlled copolymers containing AN structures, thus expanding the investigation on the relationship between the polymer structures and correlated properties.

A photo–thermal dual-regulated latent monomer strategy for sequence control of polymers

A photo–thermal dual-regulated latent monomer was used for the synthesis of polymers with advanced sequence structures.

Stereoisomeric furan/maleimide adducts as latent monomers for one-shot sequence-controlled polymerization

Two stereoisomeric latent monomers were used for one-shot sequence-controlled polymerization to create diverse sequence structures.

Synthesis of sequence-controlled polymers with pendent “clickable” or hydrophilic groups via latent monomer strategy

Herein, we designed and synthesized functional maleimide containing “clickable” or hydrophilic functional groups that was used to synthesis advanced sequence-controlled functional polymers via latent monomer strategy. A number of sequence-controlled functional polymers were synthesized by changing the polymerization temperature and controlling the initial charge ratio with highly programmable controlled temperature. Finally, a preliminary study on the thermal properties of the obtained sequence-controlled polymer revealed that the content and the distribution of the hydrophilic monomer in the polymers have a profound effect on the properties of the polymers.

Sequence-Controlled Polymers with Furan-Protected Maleimide as a Latent Monomer.

Herein, a novel methodology for preparing sequence-controlled polymers is illustrated by using a latent monomer, furan protected maleimide (FMI). At 110 °C, FMI is deprotected by retro Diels-Alder (rDA) reaction, and the released MI is immediately involved in the cross-polymerization with styrene (St) to deliver heterosegments. At 40 °C the rDA reaction does not proceed, therefore homo-poly(styrene) segments are produced. By implementing programmable temperature changes during polymerization of St and FMI, "living" polymers with tailored a sequence are created. A ternary copolymerization produces complex sequences as designed. Alkynyl-functionalized FMI, used as a latent monomer, leads to the desirable placement of functional groups along the polymer chain. This latent-monomer-based strategy opens a new avenue for fabricating sequence-controlled polymers.

Sequence‐Controlled Polymers with Furan‐Protected Maleimide as a Latent Monomer

AbstractHerein, a novel methodology for preparing sequence‐controlled polymers is illustrated by using a latent monomer, furan protected maleimide (FMI). At 110 °C, FMI is deprotected by retro Diels–Alder (rDA) reaction, and the released MI is immediately involved in the cross‐polymerization with styrene (St) to deliver heterosegments. At 40 °C the rDA reaction does not proceed, therefore homo‐poly(styrene) segments are produced. By implementing programmable temperature changes during polymerization of St and FMI, “living” polymers with tailored a sequence are created. A ternary copolymerization produces complex sequences as designed. Alkynyl‐functionalized FMI, used as a latent monomer, leads to the desirable placement of functional groups along the polymer chain. This latent‐monomer‐based strategy opens a new avenue for fabricating sequence‐controlled polymers.

Thioether-Bearing Hyperbranched Polyether Polyols with Methionine-Like Side-Chains: A Versatile Platform for Orthogonal Functionalization.

The synthesis of thioether-bearing hyperbranched polyether polyols based on an AB/AB2 type copolymerization (cyclic latent monomers) is introduced. The polymers are prepared by anionic ring-opening multibranching copolymerization of glycidol and 2-(methylthio)ethyl glycidyl ether (MTEGE), which is conveniently accessible in a single etherification step. Slow monomer addition provides control over molecular weights. Moderate dispersities (Đ = 1.48-1.85) are obtained, given the hyperbranched structure. In situ 1 H NMR copolymerization kinetics reveal reactivity ratios of rG = 3.7 and rMTEGE = 0.27. Using slow monomer addition, copolymer composition can be systematically varied, allowing for the adjustment of the hydroxyl/thioether ratio, the degree of branching (DB = 0.36-0.48), thermal properties, and cloud point temperatures in aqueous solution in the range of 29-75 °C. Thioether oxidation to sulfoxides enables to tailor the copolymers' solubility profile. Use of these copolymers as a versatile, multifunctional platform for orthogonal modification is highlighted. The methyl sulfide groups can be selectively alkoxylated, using propylene oxide, allyl glycidyl ether, or furfuryl glycidyl ether, resulting in functional hyperbranched polyelectrolytes. Reaction of the alcohol groups with benzyl isocyanate demonstrates successful orthogonal functionalization.

Probing Neuroserpin Polymerization and Interaction with Amyloid- β Peptides Using Single Molecule Fluorescence

Neuroserpin is a member of the serine proteinase inhibitor superfamily. It can undergo a conformational transition to form polymers that are associated with the dementia familial encephalopathy with neuroserpin inclusion bodies and the wild-type protein can inhibit the toxicity of amyloid- β peptides in Alzheimer's disease. We have used a single molecule fluorescence method, two color coincidence detection, to determine the rate-limiting steps of the early stages of the polymerization of fluorophore-labeled neuroserpin and have assessed how this process is altered in the presence of A β 1–40. Our data show that neuroserpin polymerization proceeds first by the unimolecular formation of an active monomer, followed by competing processes of both polymerization and formation of a latent monomer from the activated species. These data are not in keeping with the recently proposed domain swap model of polymer formation in which the latent species and activated monomer are likely to be formed by competing pathways directly from the unactivated monomeric serpin. Moreover, the A β 1–40 peptide forms a weak complex with neuroserpin (dissociation constant of 10 ± 5 nM) that increases the amount of active monomer thereby increasing the rate of polymerization. The A β 1–40 is displaced from the complex so that it acts as a catalyst and is not incorporated into neuroserpin polymers.

A novel synthetic method of a polyurethane from an aminimide as a ?latent monomer?

A novel synthetic method of a polyurethane from an aminimide as a ?latent monomer?

A novel synthetic method of a polyurethane from an aminimide as a “latent monomer”

A novel synthetic method of a polyurethane from an aminimide as a “latent monomer”

Poly(terephthalic acid anhydride) as a latent monomer in polybenzoxazole synthesis

High molecular weight poly(p-phenylenebenzobisoxazole) (PBO) was prepared from poly(terephthalic acid anhydride) (PTAA) and 1,3-diamino-4,6-dihydroxybenzene dihydrogenchloride in polyphosphoric acid (PPA). PTAA may react directly with the o-aminophenol groups to form benzoxazoles or react with PPA to generate terephthalic acid (TA) of very small particle size, which dissolves readily in PPA. PTAA provides the advantages of bypassing the requirement of small particle size TA, reducing the amount of water liberated by half, and possibly providing faster kinetics in PBO synthesis. © 1994 John Wiley & Sons, Inc.