Novel gripping structures based on van der Waals adhesive forces are disclosed. The main body has two first positioning structures. The treating is conducted a reduced pressure in the furnace, at a temperature of 1500\xb0 C. The intumescent particles may also be complexed with additional agents, such as antimicrobial agents, softening agents, pliability agent, stain resistant agents, waterproofing agents, static resistance agents and combinations thereof.