title: Intra-chain photodimerization of pendant anthracene units as an efficient route to single-chain nanoparticle fabrication.
abstract: An efficient route to architecturally defined, sub-20 nm soft nanoparticles fabricated from single polymer chains via intramolecular photodimerization of pendant anthracene units is presented. Photodimerization is confirmed by the disappearance of the characteristic anthracene π-π* absorption peak at ≈ 360 nm measured by UV-vis spectroscopy. Size exclusion chromatography (SEC) with UV, multi-angle light scattering (MALS), and viscometric detection confirms that as photodimers form, the chains fold to form nanoparticles, demonstrated by shifts in the SEC traces to longer retention times as a function of increased irradiation time. These shifts indicate a reduction in hydrodynamic radius, corroborated and quantified by viscometric data. MALS detector traces reveal the presence of a small amount of chain-chain coupling during this process, but confirm that this is primarily a single-chain phenomenon. Electron microscopy provides visual confirmation of nanoparticle formation.
authors.affiliation: Department of Chemistry and Materials Science Program, University of New Hampshire, Durham, New Hampshire, 03824, USA.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Frank
authors.affiliation: Department of Chemistry and Materials Science Program, University of New Hampshire, Durham, New Hampshire, 03824, USA.
authors.forename: Bryan T
authors.initials: BT
authors.lastname: Tuten
authors.affiliation: Department of Chemistry and Materials Science Program, University of New Hampshire, Durham, New Hampshire, 03824, USA.
authors.forename: Alka
authors.initials: A
authors.lastname: Prasher
authors.affiliation: Alan G. MacDiarmid Institute, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
authors.forename: Danming
authors.initials: D
authors.lastname: Chao
authors.affiliation: Department of Chemistry and Materials Science Program, University of New Hampshire, Durham, New Hampshire, 03824, USA.
authors.forename: Erik B
authors.initials: EB
authors.lastname: Berda
mesh_terms: D000873:Anthracenes / Q000737:chemistry*; D002850:Chromatography, Gel; D019281:Dimerization; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D010777:Photochemistry; D013056:Spectrophotometry, Ultraviolet; D014783:Viscosity
chemical_list: D000873:Anthracenes; C034020:anthracene
keywords: SEC; TEM; nanoparticles; photochemistry; polymer folding