Why does TLC keep the adsorbent layer fixed during separation?

Points on why TLC keep the adsorbent layer fixed:

• Thin layer chromatography keeps the adsorbent layer fixed on a flat support while the solvent phase moves across it to effect separation of mixture components.
• The adsorbent coating remains stationary and attached to the plate throughout the process, providing a constant separation surface.
• Only the liquid solvent flows over this fixed layer, creating movement that allows mixture components to separate without shifting the support.

You might also like more details on definition of thin layer chromatography so check it out.