Sequential SI-ATRP in μL-scale for surface nanoengineering: A new concept for designing polyelectrolyte nanolayers formed by complex architecture polymers

•pH-response of complex architecture polymer brushes generated via low-ppm SI-ATRP.•Polyelectrolyte nanolayers as complex architecture brushes were grated from Si wafer.•Sequential SI-ATRP in microliter-scale applied as novel tool for surface nanoengineering.•20 μL/cm2 of reaction mixture resulted in effective synthesis of amphiphilic polymer brushes.