General nature

1. Transparency
2. Hardness and toughness
3. Tensile and strength
4. Elastic modulus
5. Relative density
6. Refractive index
7. Wettability (surface tension, wetting angle, water absorption)

Special nature

1. Moisture content
2. Ion charge
3. Permeability (Dk value, Dk/L or Dk/t, EOP)-3.0D