title: Gold nanoparticles protected with thiol-derivatized amphiphilic poly(epsilon-caprolactone)-b-poly(acrylic acid).
abstract: Amphiphilic poly(epsilon-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) with a thiol functionality in the PCL terminal has been prepared in a novel synthetic cascade. Initially, living anionic ring-opening polymerization (ROP) of epsilon-caprolactone (epsilon-CL) employing the difunctional initiator, 2-hydroxyethyl 2-bromoisobutyrate, followed by esterification with 2,4-dinitrophenyl- or 4-monomethoxytrityl-protected mercaptoacetic acids (Prot-), provided well-defined PCL macroinitiators capped with protected thiols. The macroinitiators allowed atom transfer radical polymerization (ATRP) of tert-butyl acrylate (tBA) in a controlled fashion by use of NiBr2(PPh3)2 catalyst to produce Prot-PCL-b-PtBA with narrow polydispersities (1.17-1.39). Subsequent mild deprotection protocols provided HS-PCL-b-PAA. Reduction of a gold salt in the presence of this macroligand under thiol-deficient conditions afforded stable, aggregation-free nanoparticles, as evidenced from UV-vis spectroscopy and transmission electron microscopy (TEM), the latter revealed nanoparticles with a mean diameter of 9.0+/-3.1 nm.
authors.affiliation: Technical University of Denmark, Department of Chemical and Biochemical Engineering, Danish Polymer Centre, Building 423, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Irakli
authors.initials: I
authors.lastname: Javakhishvili
authors.forename: Søren
authors.initials: S
authors.lastname: Hvilsted
mesh_terms: D000180:Acrylic Resins / Q000138:chemical synthesis / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D015394:Molecular Structure; D010316:Particle Size; D011091:Polyesters / Q000138:chemical synthesis / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D011091:Polyesters; D013438:Sulfhydryl Compounds; D013501:Surface-Active Agents; C538905:poly(epsilon-caprolactone)-b-poly(acrylic acid); D006046:Gold