Hybrid Aluminum Colored Pigments Based on Gradient Copolymers Design

A colored polymer/aluminium hybrid pigment was synthesized by nitroxide mediated polymerization initiated from an inorganic surface. This approach requires the preparation of a vinyl dye monomer able to copolymerize with n ‐butyl acrylate (n‐BuA) and styrene (S) from the surface of aluminium flakes. The linearity of the ln([M] 0 /[M] t ) and of the $\overline M _{\rm n}$ as a function of time and conversion constitute the criteria of control/“living” polymerization, i.e. linearity of respectively ln([M] 0 /[M] t ) =  f (t) and the $\overline M _{\rm n}$  =  f (conversion) plots. Kinetic measurements reveal an upward deviation from the linearity for n ‐BuA polymerization for very high conversion. The introduction of S monomer restores the control of the polymerization. Both the length of the grafted chains and the dye/styrene molar ratio influence the color of the hybrid material.