A facile approach to architecturally defined nanoparticles via intramolecular chain collapse.
A novel approach is presented for the controlled intramolecular collapse of linear polymer chains to give well-defined single-molecule nanoparticles whose structure is directly related to the original linear polymer. By employing a combination of living free radical polymerization and benzocyclobutene (BCB) chemistry, nanoparticles can be routinely prepared in multigram quantities with the size being accurately controlled by either the initial degree of polymerization of the linear chain or the level of incorporation of the BCB coupling groups. The latter also allows the cross-link density of the final nanoparticles to be manipulated. In analogy with dendritic macromolecules, a significant reduction of up to 75% in the hydrodynamic volume is observed on going from the starting random coil linear chains to the corresponding nanoparticles. The facile nature of the living free radical process also permits wide variation in monomer selection and functional group incorporation and allows novel macromolecular architectures to be prepared. Furthermore, the use of block copolymers functionalized with benzocyclobutene groups in only one of the blocks gives, after intramolecular collapse, a hybrid architecture in which a single linear polymer chain is attached to the globular nanoparticle.
Harth
Eva
E
Center for Polymeric Interfaces and Macromolecular Assemblies, IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099, USA.
Van Horn
Brooke
B
Lee
Victor Y
VY
Germack
David S
DS
Gonzales
Chad P
CP
Miller
Robert D
RD
Hawker
Craig J
CJ
D000180:Acrylic Resins / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D011083:Polycyclic Compounds / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry
D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D011083:Polycyclic Compounds; D011108:Polymers; D011137:Polystyrenes; D011092:Polyethylene Glycols; C079040:benzocyclobutene