TABLE 2.

The relationship between RCR time at 30 °C and NF sizes.

RCR reaction time	NF size or description
0.5 h	Only amorphous bulky structures are observed in SEM imaging
1 h	Some crystal-like structures become visible
2 h	Petal-like structures are formed on the surface
3 h	Flower-like spherical structures are gradually formed on the matrices
6 h	~150 nm
8 h	~200 nm
10 h	200–300 nm
15 h	~500 nm
20 h	~1 μm
30 h	2–4 μm