Surface-initiated ATRP was applied for the step-by-step growth of the biomimetic amphiphilic block copolymer membrane on a gold support. Different thicknesses of membranes were achieved through the variation of the polymerization conditions. The OH-groups of the hydrophilic polymer blocks can be further functionalized to tune the membrane properties. Synthesis, characterization, and solvent-responsive properties of the amphiphilic triblock copolymer membrane are presented.