Figure 8: The schematic mechanism of stretches of a semen droplet. (A) At V=0, LC molecules are aligned along y-direction. The fertile and infertile sperms swim randomly. (B) When the voltage is applied to the left of LCPCF, the LC molecules tilt up and the left LCPCF is more hydrophilic. The induced fluidic flow (white arrow) washes away all the sperms meanwhile the fertile sperms swim upstream against the flow. (C) When the voltage turns off, the wettability of LCPCF is same as (A) and the semen drop stretches back. (D) At V=0, the infertile sperms disperse in the semen drop. (E) When the voltage is applied to the left region of LCPCF, the induced fluidic flow (white arrow) washes away all the sperms. (F)(G) The infertile sperms are deposited on the left region.