Influence of Solvent Size on Structural Properties of Bottle-brush Polymers

We proposed a modified dissipative particle dynamics simulation model by which one can effectively avoid the bond-crossing problem, and investigated the effect of solvent size on the structural properties of bottle-brush polymers in dilute solution on the basis of this model. It was found that with the increase of solvent size, the radius of the gyration of the bottle-brush polymer decreases considerably in the athermal solvent but increases in the selective solvent favoring the backbone, respectively.

Efficient synthesis of bottle-brush polymers enabled by selective photoactivation strategy in NIR-induced PET-RAFT polymerization

Bottle-brush polymers possessing densely grafted side chains have special properties that are distinct from linear macromolecules.Herein,an efficient method for preparing bottle-brush polymers based on a selective photoactivation strategy in the photoinduced electron/energy transfer reversible addition-fragmentation chain transfer(PET-RAFT)polymerization was developed.A methacrylate monomer 2-(2-(dodecylthiocarbonothioylthio)propionate)ethyl methacrylate(DTPEMA)containing a 2-(dodecylthiocarbonothioylthio)propionate(DTP)unit with a secondary R group was designed.Utilizing the unique selectivity of metal naphthalocyanine photocatalyst zinc 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine(ZnTtBNc)toward trithiocarbonate with tertiary R group,the PET-RAFT polymerization of DTPEMA catalyzed by ZnTtBNc was performed under near infrared(NIR)light(λ_(max)=760 nm)irradiation at room temperature,using 4-cyano-4-[(dodecylsulfanylthiocarbonyl)-sulfanyl]pentanoic acid(CDTPA)with a tertiary R group as a chain transfer agent(CTA).Proton nuclear magnetic resonance(1H NMR)and gel permeation chromatography(GPC)results demonstrated that the DTP units in the side chains were inert during the polymerization.By grafting poly(methyl acrylate)(PMA)from PDTPEMA via thermal-initiated RAFT polymerization,welldefined P(DTPEMA-g-PMA)bottle-brush polymers could be afforded.Furthermore,the film prepared from the bottle-brush polymer exhibited excellent scratch self-healing property due to the interlocking of side chains.