Salicylaldehyde-functional diblock copolymer nano-objects were synthesized by polymerization induced self-assembly (PISA) via RAFT dispersion polymerization of a newly designed core-forming monomer, 3-formyl-4-hydroxybenzyl methacrylate (FHMA), using poly(2-hydroxypropyl methacrylate) (PHPMA) macromolecular chain transfer agent as a steric stabilizer in methanol at 65 o C. A range of PHPMA-b-PFHMA block copolymer morphologies including sphere, worm and vesicle could be accessed by adjusting the degree of polymerization of core forming block PFHMA. Since the salicylaldehyde groups of core-forming PFHMA blocks could react with hydrazine in a 2:1 stoichiometry to form salicylaldazines with aggregation-induced emission, one-step post-modification of the PISA nano-objects using hydrazine enabled their inherent nanostructures to be stabilized via covalent cross-linking and simultaneously conferred luminescent features on the resulting stabilized nanoparticles. Solid nano-objects, obtained easily via precipitation into diethyl ether, could be re-dispersed well in methanol and THF. The nano-objects could also be re-dispersed in water to form colloidal dispersions at a low concentration (≤ 1% w/w). Thanks to the stability imparted by the cross-linking, the morphologies of the preformed PISA nano-objects remained intact even after re-dispersing these cross-linked nano-objects in THF (a good solvent for both blocks). The stabilized nano-objects displayed strong orange fluorescence in water, organic solvents or solid states. This work opens the possibility for simultaneous functionlization and stabilization of PISA-generated block copolymer nano-objects. Materials 2-Hydroxypropyl methacrylate (HPMA; J&K, 97%) was passed through a column of basic alumina to remove inhibitor and then stored at -20 °C prior to use. 2, 2′-Azobis(isobutyronitrile) (AIBN; Sinopharm Chemical Reagent, 99%) was purified by recrystallization from ethanol. 4-Cyano-4-(propylthiocarbonothioylthio)pentanoic acid (CPPA) 53 and 5-(chloromethyl)-2-hydroxybenzaldehyde 54 were synthesized according to literature procedures. Other reagents were all analytical grade and used as received. Synthesis of 3-formyl-4-hydroxybenzyl methacrylate (FHMA)A mixture of methacrylic acid (25.8 g, 0.3 mol), sodium hydroxide (12.0 g, 0.3 accelerating voltage of 120 kV. For preparation of TEM samples, a drop of diluted dispersion (0.15 % w/w) solution was deposited onto a carbon-coated copper grid and dried under ambient conditions. All samples were not stained. Results and discussion Synthesis of monomer 3-formyl-4-hydroxybenzyl methacrylate (FHMA)A novel salicylaldehyde functionalized methacrylate monomer FHMA was designed and synthesized readily by the reaction of methacrylic acid with 5-(chloromethyl)-2-hydroxybenzaldehyde (Scheme 1). The structure of FHMA was confirmed on the base of the elemental analysis, MS, and 1 H NMR spectroscopy. The 1 H NMR spectrum (Fig. 1) exhibits the characteristic signals corresponding to methacrylic vinyl (a,b), aldehyde (i) and hydroxyl (h) mo...

Photo-crosslinkable and amine-containing block copolymer nanoparticles are synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization-induced self-assembly of a multifunctional core-forming monomer, 2-((3-(4-(diethylamino)phenyl)acryloyl)oxy)ethyl methacrylate (DEMA), using poly(2-hydroxypropyl methacrylate) macromolecular chain transfer agent as a steric stabilizer in methanol at 65 °C. By tuning the chain length of PDEMA, a range of nanoparticle morphologies (sphere, worm, and vesicle) can be obtained. Since cinnamate groups can easily undergo a [2 + 2] cycloaddition of the carbon-carbon double bonds upon UV irradiation, the as-prepared block copolymer nanoparticles are readily stabilized by photo-crosslinking to produce anisotropic nanoparticles. The crosslinked block copolymer nanoparticles can be used as templates for in situ formation polymer/gold hybrid nanoparticles.

A novel acrylate monomer was synthesized by facile sequential two-step reactions and polymerized using RAFT polymerization to yield a well-defined thermo-, pH- and CO2-responsive homopolymer.

A multi-functional polymer with aggregation-induced emission (AIE)-active salicylaldehyde azine (SA) functionality and reactive oxygen species (ROS)-responsive thioether groups is readily prepared via thiol-ene click polymerization of SA derivative diacrylate monomer, poly­(ethylene glycol) diacrylate, and 3,6-dioxa-1,8-octanedithiol. The obtained AIE-active polymer exhibited an unexpected strong emission in amide solvents compared to that in other common organic solvents that was dramatically decreased by adding a trace amount of water, suggesting that the polymer could be utilized as a water trace indicator in amide solvents. In the backbone, the PEG segments make the polymer well dispersed in water and the ROS-responsive thioether groups enable this polymer as a promising ROS scavenger, with embedded SA moieties as a fluorescent indicator for the hemolysis determination. Due to the ability of SA moieties to complex with Cu2+, this AIE polymer can also be utilized as a fluorescent sensor for selective Cu2+ detection in real-world water samples. Thus, this multi-functional polymer is anticipated to be well applied in biological and environmental applications.

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