Table 3. The average van der Waals force on abalone abdominal foot (unit: N).

Number of test	The average van der Waals force (N)
	Smooth acrylic	Through-hole acrylic	Striped grooved acrylic	Smooth Teflon	Through-hole Teflon
1	23.19	12.47	15.41	20.45	18.46
2	22.43	20.01	10.96	19.22	19.48
3	21.55	17.16	11.69	20.94	18.34
4	21.17	18.76	11.48	20.94	19.71
5	23.08	10.78	16.49	20.37	18.90
6	24.18	19.45	19.20	20.56	16.93
7	21.17	17.42	15.65	20.94	16.12
8	22.12	17.48	16.80	20.25	19.31
9	20.33	18.04	13.99	19.87	17.62
10	19.80	18.23	22.53	19.15	18.23