What is in dishwashing detergent that causes it to break hydrogen bonds?
September 30th, 2009 | by bonds |
whosit? asked:
Dawn dishwashing detergent breaks up grease and the washing water itself. I tried to research what ingredient allows it to cleave the hydrogen bonds and break the surface tension of the water but all that comes up on the search engines are Dawn advertisements. DOES ANYONE KNOW WHY DISHWASHING DETERGENT CLEAVES HYDROGEN BONDS?
Dawn dishwashing detergent breaks up grease and the washing water itself. I tried to research what ingredient allows it to cleave the hydrogen bonds and break the surface tension of the water but all that comes up on the search engines are Dawn advertisements. DOES ANYONE KNOW WHY DISHWASHING DETERGENT CLEAVES HYDROGEN BONDS?
Can you also cite a source?
MOHAMED
5 Responses to “What is in dishwashing detergent that causes it to break hydrogen bonds?”
By JOHN K on Oct 1, 2009 | Reply
SAMUEL
enzemes
By Nick F on Oct 4, 2009 | Reply
MIKEL
they aren’t breaking any hydrogen bonds, I believe they just aid in the emulsification of oil/grease
By tkbisign on Oct 6, 2009 | Reply
RODGER
“Detergent molecules have two very different parts–a polar or ionic part, such as a sulfonate group, and a non-polar part, consisting of a long hydrocarbon chain. (In the case of soap, a type of detergent, the polar group is carboxylate.) The polar part of the molecule is hydrophilic, meaning that it is attracted to water. The nonpolar part is hydrophobic, meaning that it is repelled by water.”
“When you introduce detergent molecules into water, the hydrophobic groups change the structure of the water and interfere with hydrogen bonding between the water molecules. Consequently, the hydrophobic groups are expelled to the surface of the water, where the detergent molecules are oriented with their hydrophilic ends in the water and their hydrophobic groups away from it. For this reason, molecules such as detergents are often called surfactants, or surface active agents. The replacement of water molecules by detergent molecules results in a decrease in the surface tension of water.”
The source isn’t the best type in the world, but the facts seem to be efficient and surprisingly accurate.
By Spacebunny on Oct 8, 2009 | Reply
THEODORE
I figured it must be the soap detergent molecules themselves that create the effect, since the detergent molecule has a polar end and a long nonpolar tail. It orients itself so that the polar end is toward the water molecules and the ‘tail’ is away from the water (the ‘micelle’ formation). This is what emulsifies grease but it has surface effects on water as well (as the soap will form spheres in order to minimize contact with the water).
A better explanation in short came from an “Ask a Scientist” site I found: Soap or detergent molecules tend to aggregate at the
surface of the water, where their non-polar tails stick out away from the water. At the surface, these molecules interfere with the dipole-dipole interactions among water molecules, thereby reducing surface tension, often as much as 90 percent.
There are more answers and information there, so I’ve linked it below.
By Stonerscientist on Oct 10, 2009 | Reply
RUSTY
most soap is slightly caustic, (pH higher than 8.5) this might be what you are observing.