Surface Tension

hydrophilic HLB is low or high?

HIGH

Tweens have low/high HLB?

High (9.6-16.7)

lipophilic HLB is low or high?

LOW

What is surface tension?

Molecules on top can only interact with the molecules below them. The molecules on top are pulled down because there are no molecules above them pulling upward. The surface contracts and results in surface tension.

If two liquids are completely mixed, is there any interfacial tension?

NO

the work required to increase surface A of the liquid by 1 area unit

Surface free energy

surface tension definition

The "tension" in the surface is the force per unit length that must be applied parallel to the surface as to counterbalance the net inward pull

T/F. Surface tension is greater than interfacial tension.

True

negative adsorption

added materials are partitioned more in favor of bulk

name some antifoaming agents?

alcohol, ether, castor oil, and some surfactants

Hydrogen bonding increases ____ in liquids?

cohesion

Surfactants that are used to remove dirt

detergents

relatively stable structure consisting of air pockets enclosed within thin films of liquid

foam

amphiphile

has affinity for both polar and non-polar groups

expansion of the surface increases/decreases the energy of the system?

increases

Force per unit length existing at the interface between two immiscible liquids

interfacial tension

spans have low/high HLB?

low (1.8-8.6)

foaming agent does what?

stabilizes the gas-in-liquid dispersion

Molecules or ions that are adsorbed at interfaces

surfactants or surface acting agents

positive adsorption

the added molecules are partitioned in the favor of the interface

most important property of a wetting agent?

to lower the contact angle between a liquid droplet and surface over where it spreads

surfactant that, when dissolved in water lowers the advancing contact angle and aids in displacing an air phase at the surface and replacing it with a liquid phase

wetting agent