Linear and star block copolymer (BCP) nanoassemblies of [poly(4-vinylpyridine)-block-polystyrene] n ([P4VP-b-PS] n ) with different arm numbers have been synthesized by RAFT dispersion polymerization under formulation of polymerization-induced self-assembly (PISA). All RAFT dispersion polymerizations employing mono-and multifunctional macromolecular chain transfer agents proceed with similar polymerization kinetics. The size and/or morphology of [P4VP-b-PS] n nanoassemblies are firmly correlative to arm number n, and star [P4VP-b-PS] n BCPs have more complex morphology than the linear counterpart. Several interesting morphologies of star BCPs including small-sized vesicles and porous nanospheres have been synthesized, and they are compared with those of the linear counterpart. Our research indicates that topology is a significant parameter to dedicate the size and morphology of star BCP nanoassemblies under PISA conditions.
SnSe/rGO nanocomposites can be synthesised in situ via a facile solution method; once sintered, the lattice thermal conductivity and ZT of the composites are significantly reduced and enhanced respectively compared to SnSe itself.
This review focuses on the synthesis of multicompartment block copolymer nanoparticles (MBCNs) via solution self-assembly and polymerization-induced self-assembly (PISA).
Linear photoresponsive
polyurea of PbAzo containing bridged-azobenzene
moieties in backbone was synthesized via polyaddition reaction between
hexamethylene diisocyanate and cis-3,3′-diamino
ethylene-bridged azobenzene. The bridged-azobenzene moieties endow
the PbAzo polyurea advantages of visible-light-driven isomerization
and fast and powerful photoresponse. Under irradiation with 405 nm
blue light, stable cis-PbAzo converts into metastable trans-PbAzo accompanying the amorphous-to-crystalline transition
and the yellow-to-red color change via cis-to-trans isomerization. With further illumination with 532
nm green light, trans-to-cis isomerization
reversibly takes place. This photoresponsive polyurea is used in photopatterning,
in which patterns can be reversibly written or erased alternatively
by 405 nm blue light and 532 nm green light or heating. Besides, the
polyurea film can act as qualified visible-light-driven actuators.
Under irradiation with 405 nm blue light, it initially bends away
the light source with the bending angle above 110 deg in several seconds,
and then it recovers to its initial state with no attenuation under
irradiation with 532 nm green light. Our photoresponsive polyurea
is different from photoresponsive polymers including planar azobenzene
moieties, and this polyurea is expected to be promising for smart
materials.
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