Table 1:

The evolution of size and Zeta potential of PU microstructures.

Period, days	Measured values at. different pH
	3.0		7.0		10.0
	Mean size, nm	Zeta potential, mV	Mean size, nm	Zeta potential, mV	Mean size, nm	Zeta potential, mV
1	144	24.5	147	24.8	142	24.7
3	138	24.6	143	24.5	139	24.1
5	131	24.8	131	24.6	130	23.9
7	126	25.1	127	24.7	122	23.5
9	118	25.4	125	24.8	119	23.3
11	117	25.5	125	24.9	120	22.9
13	111	26.4	123	24.3	118	22.0
15	108	27.1	122	24.0	117	20.7