The invention discloses an energy-consumption-free
liquid crystal color recyclable writing tool and a preparation method thereof, and belongs to the field of
liquid crystal materials and display. The recyclable writing tool comprises a writing board and a writing pen; the writing board is made of a
cholesteric liquid crystal polymer film; the writing pen is dipped with pen ink with different
hydrogen ion concentrations; the
cholesteric liquid crystal polymer film has the characteristic of reflecting circularly polarized light with single rotation, and the concentration change of
hydrogen ions can cause expansion or compression of a
polymer grid, so that the screw
pitch of the
cholesteric liquid crystal is changed, the reflection band of the cholesteric
liquid crystal is adjusted, and the color of the cholesteric liquid
crystal polymer film is changed. After the writing pen writes on the writing board, the cholesteric liquid
crystal polymer film of the writing board absorbs
moisture and volatilizes, the film returns to be colorless again, and meanwhile, the film is cleaned again by using an alkaline solution to return to a colorless state, so that recycling is realized; the method has the advantages of high response speed, rich color, recyclability, low cost and the like.