How does cling film, cling?

Plastic wrap hangs on to everything it touches like grim death. Find out how it manages to glom on to nearly every surface in a kitchen.

There is a debate about what is more the more responsible substance to use: cling wrap or aluminum foil. In this author’s opinion, the clear winner is aluminum foil. Why? Because it’s the only one that works. Aluminum foil is a humble but hard-working substance. Plastic wrap is an ironed-out version of the blob. It’s a confusingly clear substance that sticks to everything in sight, including one’s hands and itself, until it’s a wadded-up ball of plastic sitting next to a still-uncovered plate of brownies. How does it manage to grab onto everything so well?

Many sources say that it is static cling that keeps the wrap holding tight to everything around it. The plastic acquires a charge and sticks itself to anything with an opposite charge. Many plastic bowls carry a very slight negative charge along their surface, giving the wrap something to hang onto – or be repulsed by. But cling wrap also manages to hang on to metal – which conducts electricity and so would eliminate a difference in charge – and glass, and itself. Some plastic wrap is hydrophilic, grabbing on to any water it gets close to. Some is hydrophobic, repelling water. Water, unless it’s pure, also conducts electricity. Plus, all wraps wad up like dirty laundry, or stick on like burrs. If static electricity made them work, they would sometimes be repelled by themselves, or other substances. That would make them impractical to use. It’s materials science, not electric charge, that gives cling wrap its clinginess.

So how do cling wraps grip? Added adhesives. Other chemicals, all minor adhesives, are added to make the cling wraps sticky enough to do their jobs. These adhesives don’t completely mix with the LDPE or PVC, so they are available to grab anything that comes by. Cling wraps stick on to things the same way a piece of tape does.

Edited from How does cling wrap cling? – io9.

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