the.com/semipermeable
a membrane with a bouncer's judgment: some molecules on the list, some not.
means a material that lets certain substances pass through while blocking others, usually based on size, charge, or solubility.
from from latin semi (half) plus permeare (to pass through) — coined in 19th-century chemistry as scientists like thomas graham studied diffusion and osmosis through animal membranes and artificial films.
cell membranesevery living cell relies on this exact trick
osmosis driverwater crosses freely, solutes often cannot
kidney dialysismachines mimic this to filter blood
water purificationreverse osmosis forces water through, blocks salt