Clean, gold-coated glass substrates were first soaked in ω-mercaptoundecyl bromoisobutyrate solution (0.2 mM in ethanol) for overnight to get initiator-coated substrates. The initiator-coated substrates, together with copper(I) bromide (14.35 mg and 0.1 mmol), were then placed into a Schlenk tube and deoxygenated via pump vacuum for 10 cycles. TMAO monomer (1.72 g and 10 mmol), Me6TREN (23 mg and 0.1 mmol), methanol (3.6 ml), and H2O (0.4 ml) were added into Schlenk tube and deoxygenated via the same method. After full deoxygenation, the mixed aqueous solution of TMAO monomer and Me6TREN were transferred to the tube, which held the substrate and copper bromide. The reaction mixture was placed at ambient temperature overnight. The substrate was then taken out from the mixture and washed with alternating ethanol and water, three times each, and air-dried before being used as SPR sample. The thickness of the coated TMAO polymer film was measured by ellipsometer.