Initiator deposition was conducted according to the same protocol as for silicon wafers but using a larger volume of solution to completely cover the surface of the blocks. Initiator-functionalised NR blocks were placed in an in-house built sealed reaction chamber and placed under an argon stream (for 10 min) to remove oxygen. Brush synthesis was carried out by injection of 30 mL of solution and allowed to proceed for 22 min. The reaction was stopped through the addition of oxygenated (air) deionised water. Copious amounts of water and ethanol were then used to rinse the substrate surface. Ellipsometry measurements confirmed the target thickness. PMETAC blocks were generated similarly as for silicon wafers. NR blocks were stored in a nitrogen box prior use.