A new aldehyde-functionalized glycomonomer, 1,2:3,4-di-O-isopropylidene-6-O-(2′-formyl-4′vinylphenyl)-D-galactopyranose (IVDG), was designed and prepared. The "living"/controlled radical polymerization of IVDG was successfully achieved using 2,2′-azobis(isobutyronitrile) as the initiator and 1-phenylethyl dithiobenzoate as the reversible addition-fragmentation chain transfer (RAFT) agent at 60 °C in tetrahydrofuran. The polymerization followed first-order kinetics, the number-average molecular weight of the obtained polymers increased in direct proportion to the monomer conversion, and the molecular weight distribution was narrow (polydispersity index <1.1). Removal of protective isopropylidene groups from the sugar residue in polyIVDG was carried out quantitatively using 88% formic acid at room temperature, yielding a novel amphiphilic polymer containing both galactopyranose and aldehyde functionalities. These amphiphilic polymers self-assembled into well-defined aldehyde-bearing polymeric micelles in aqueous solution without recourse to any surfactant. The size of the micelles increased almost linearly with the molecular weight of polyIVDG precursor, which could be controlled directly via the aforementioned RAFT polymerization process. Protein-bioconjugated nanoparticles were also successfully prepared by the immobilization of bovine serum albumin (as a model protein) onto the aldehyde-functionalized micelles.

A facile synthetic pathway to poly(N-isopropylacrylamide) (PNIPAM)−poly(ethylene glycol) (PEG) miktoarm star copolymers with multiple arms has been developed by combining reversible addition−fragmentation chain transfer (RAFT) polymerization and aldehyde−aminooxy “click” coupling reaction. Star PNIPAM with aldehyde functionalized core was initially prepared by the RAFT arm-first technique via cross-linking of the preformed linear macro-RAFT agents using a newly designed aldehyde-containing divinyl compound 6,6′-(ethane-1,2-diylbis(oxy))bis(3-vinylbenzaldehyde) (EVBA). It was then used as a multifunctional coupling agent for the subsequent formation of the second-generation PEG arms via the click coupling reaction between its aldehyde groups and aminooxy-terminated PEGs. The thermoresponsive micellization behavior of PNIPAM−PEG miktoarm star copolymer with different PEG arm numbers in water was also investigated. Opportunities are open for thermoinduced intermolecular or intramolecular micellization of PNIPAM−PEG miktoarm star copolymers via controlling the content ratio of PNIPAM and PEG, forming multimolecular micelles and unimolecular micelles, respectively.

No abstract

No abstract

A new monomer, 2-formal-4-vinylphenyl ferrocenecarboxylate (FVFC), containing both aldehyde and ferrocene functional groups was designed and prepared by the reaction of ferrocenecarboxylic acid chloride with 2-hydroxy-5-vinylbenzaldehyde. The controlled radical polymerization of FVFC was achieved using 2,2′azobis(isobutyronitrile) (AIBN) as the initiator and 2-cyanopropyl-2-yl dithiobenzoate (CPDB) as the reversible addition-fragmentation chain transfer (RAFT) agent at 60 °C in tetrahydrofuran (THF). The polymerization nearly followed first-order kinetics, the number-average molecular weight of the obtained polymers increased almost in direct proportion to the monomer conversion, and the molecular weight distribution was narrow (polydispersity index < 1.2). The chain and terminal structures of the obtained polyFVFC were confirmed by 1 H NMR and matrix-assisted laser desorption-ionization time-of-flight mass spectrometry analysis. The obtained polyFVFC can be employed as a macro-RAFT agent for styrene polymerization, resulting in polyFVFC-bpolystyrene.