This paper presents on a new damping element called the colloidal damper which is used a
principle of surface extension force in nano pore. The direction acting of the surface extension force
of water in hydrophobic nano pore is different in pressurization and decompressurization processes
[1,2]. This principle is applied to a damping element. The nano pore is constructed by silica gel. A
silica gel ball of 100-200 micrometer dia. has many nano pores of 5-20 nanometer dia. in it [3,4].
The coated spherical silica gel and water are inserted in a piston - cylinder unit in order to work as a
damper. If compression and decompression forces are added to the piston - cylinder unit (damper),
water flows into and moves out the nano pore under balance of pressure. A contact angle of
compression formed by the hydrophobic nano pore and water is larger than that of decompression.
This difference of the contact angle produces a damping energy.
In this paper, behavior of water in the pore of silica gel is investigated using the molecular
dynamics. Dissipation energy of the colloidal damper is concerned with the contact angles of water
in the pore. So the contact angles are calculated for changing parameters, i.e. size of the pore, length
of the hydrophobic material, velocity (pressure) of water flows into the pore. Then these results are
compared with the experimental ones.
Role of hydrogen in affecting the growth trend of CNT on micron spherical silica gel