Tween 20 (Non-ionic)

Tween (full name Tween 20 or Polysorbate 20) is a common detergent used in biology used in cell lysis and membrane protein solubilisation among other uses.

Polyoxyethylene(20)sorbitan monolaurate used to solubilise proteins. Hydrophobic membrane proteins are suited to more non ionic detergents.

MSDS Sheets

CAS 9005-64-5

Used in buffers to reduce ionic effects used  with peptides and proteins