Figure 1: (a) A schematic illustration of microwave heating system. (b) Microwave power (solid line) and solution temperature (open circle) profiles during microwave synthesis of colloidal PEG-AuNPs. The two different temperature ramping rates ( ) of 124.2°C/min and 34.2°C/min are created by adjusting the applied microwave power during the initial stage (ramping region). After the temperature ramping, the solution temperature is maintained at 90°C using a microwave power of 10 W (retention region).