A Facile Method to Form a Densely Grafted PEO-b-P4VP Brush on Gold Surface

Here we report a facile method for the preparation of a PEO113-b-P4VP93 brush on gold surface with a grafting density as high as 1.32 chains/nm2; the P4VP blocks were physically adsorbed on gold surface forming an inner layer while the PEO blocks stretched towards the solution forming PEO brush. PEOl13-b-P4VPq3 micelles with P4VP core and PEO shell formed in methanol/water mixed solvents were used as the precursor. By adsorbing PEOII3-b-P4VP93 micelles from pure water, in which the density of the micelles is the largest, maximum amount of the micelles was adsorbed onto gold surface, and the adsorbed micelles existed as individual domains on the surface To prepare the polymer brush with a density as high as possible, we annealed the adsorbed micelles by metha- nol/water mixed solvent at the volume fraction of methanol （VF） of 20%, which was the proper proportion at which the core-forming P4VP chains began to be flexible but the integrity of the micelles was remained. At this volume fraction, almost all the adsorbed micelles originally existing as individual domains were transformed into a dense polymer brush.