EtOH as disinfectants

• Ethanol is amphipathic, so it can interact with both water and lipid molecules, and thus it can insert into and disrupt the phospholipid membrane, making it more permeable and allowing it to enter the cell.
• Ethanol also denatures proteins by disrupting hydrogen bonds and hydrophobic interactions, causing proteins to unfold and lose function. 
• Around 70% works best because water helps ethanol penetrate cells and slows evaporation, giving more time for damage; in contrast, 100% ethanol dehydrates the outside too quickly and is less effective at penetrating and killing cells.