Scaling relations and size control of block ionomer microreactors containing different metal ions

Block ionomer micelles of polystyrene-b-poly(metal acrylate) containing a wide range of metal ions have been characterized, in order to establish a priori size control for a system of inorganic microreactors in which metal ions can be converted via simple chemistry to metallic or semiconducting nanoparticles. A variety of techniques have been employed, including size-exclusion chromatography (SEC), static light scattering (SLS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Scaling relations for aggregation numbers (Z) and ionic core radii (R-core) as a function of the ionic block length (NB) have been determined: Z similar to N-B(0.74+/-0.08); R(core)similar to N-B(0.58+/-0.03), where the proportionality and K-Z,K-ave and K-R,K-ave are dependent on the metal ion and decrease as Ni2+ > Cs+ > Co2+ > Ca2+ > Cd2+ > Pb2+. For most metal ions, linear plots of R-core vs N-B(0.58) yield correlation coefficients of r(2) of ca. 0.99, indicating excellent size control of ionic core radii. We also find that K-Z,K-ave decreases linearly with the crystal ionic radius (r(ion)) for block ionomers neutralized with metal acetates. We speculate upon the role of the metal ion on micelle growth. Comprehensive scaling laws have also been determined to include the soluble block length dependence, and similar exponents were found for most metal ions. DLS results show R-g/R-h values between those of stars and compact spheres. The coronal brush height (E-T) is found to scale as H similar to Z(0.3+/-0.1)N(A)(0.9+/-0.2), in, reasonable agreement with the Daoud and Cotton model for starlike systems.