Intra‐Chain Photodimerization of Pendant Anthracene Units as an Efficient Route to Single‐Chain Nanoparticle Fabrication
2013; Wiley; Volume: 35; Issue: 2 Linguagem: Inglês
10.1002/marc.201300677
ISSN1521-3927
AutoresPeter Frank, Bryan T. Tuten, Alka Prasher, Danming Chao, Erik B. Berda,
Tópico(s)Block Copolymer Self-Assembly
ResumoAn 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. image
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