Double-Hydrophilic Block Copolymers with Monophosphate Ester Moieties as Crystal Growth Modifiers of CaCO₃

Abstract

The synthesis of double-hydrophilic block copolymers with a poly(ethylene glycol) block (PEG) and a block with pendant monophosphate ester groups based on a hydroxylated polybutadiene block (poly[2-(2-hydroxy ethyl)ethylene] (PHEE) with variable degrees of phosphate substitution (up to 40%) is described. It is shown that these block copolymers are very efficient scale inhibitors for CaCO3. The efficiency of these polymers is compared with block copolymers with an ionic block based on phosphorylated polyglycidol (PGL) with phosphorylation degrees up to 100%. The phosphorylated polyglycidols were also used to modify the morphology of CaCO3 crystals. Instead of the typical rhombohedral calcite single crystals, superstructures of nanometer-sized particles are formed in the presence of these block copolymers when two different techniques were used: the fast double-jet technique and the slow Kitano-method. In the double-jet method, only spherical superstructures are obtained, whereas for the slower growth region covered by the Kitano method, complex cone-like or flower-like superstructures are formed.