Synthesis of Poly(<i>n</i>-butyl acrylate)-<i>block</i>-poly(acrylic acid) Diblock Copolymers by ATRP and Their Micellization in Water Olivier Colombani Markus Ruppel Frank Schubert Heiko Zettl Dmitry V. Pergushov Axel H. E. Müller 10.1021/ma0609578.s001 https://acs.figshare.com/articles/journal_contribution/Synthesis_of_Poly_i_n_i_butyl_acrylate_i_block_i_poly_acrylic_acid_Diblock_Copolymers_by_ATRP_and_Their_Micellization_in_Water/3002275 Amphiphilic diblock copolymers, poly(<i>n</i>-butyl acrylate)-<i>block</i>-poly(acrylic acid) (P<i>n</i>BA-PAA), with narrow molecular weight distribution (PDI ≤ 1.07) were prepared by atom transfer radical polymerization (ATRP) of <i>n</i>-butyl acrylate and <i>tert</i>-butyl acrylate (<i>t</i>BA), followed by selective acidolysis of the P<i>t</i>BA block. These polymers possess a soft P<i>n</i>BA hydrophobic block with a constant chain length of 90−100 monomer units and pH- and ionic strength-sensitive hydrophilic PAA block with DP<sub>PAA</sub> = 33−300 AA monomer units. They were expected to form stimuli-responsive micelles. The block copolymers with DP<sub>PAA</sub> ≥ 100 are directly soluble in water at pH > 4.7. Pyrene steady-state fluorescence spectroscopy and fluorescence correlation spectroscopy (FCS) studies indicate the existence of a very low critical micelle concentration (cmc ∼ 10<sup>-8</sup> mol/L). The number-average hydrodynamic radii of the micelles, as determined by FCS, range from 28 to 55 nm, depending on the PAA block length. FCS data indicate that micellar sizes significantly decrease upon dilution for salt-free systems. This is attributed to a dynamic, but kinetically controlled, behavior of these self-assembled nanostructures. In saline solutions the micellar sizes remain constant above the “apparent” cmc (cmc*), which is attributed to slower dynamics of unimer exchange between micelles. 2007-06-12 00:00:00 micellar sizes fluorescence correlation spectroscopy monomer cmc acid micelle WaterAmphiphilic diblock copolymers DPPAA PAA block length pH FCS ATRP PDI acrylate