Soft Materials Soft Materials
Toothpaste Toothpaste
Detergent Detergent
By: By:
Jennifer, Jackie, Nicole, Dustin and Jennifer, Jackie, Nicole, Dustin and Steve
Steve
•Cells are held intact by the 'cytoskeleton', a
network of protein fibres inside the cell. Ben Fabry, from the Harvard School of Public Health in Boston, and colleagues measured how this scaffolding deforms under a range of forces by attaching tiny magnetic
beads to cytoskeletons, and applying an oscillating magnetic field1.
•Just as toothpaste stays solid in its tube, until given enough of a squeeze that it flows obligingly onto your toothbrush, so the cytoskeleton holds together like a solid most of the time. But under the right conditions, it transforms easily into something more like a fluid,
accommodating expansion, contraction or division.
P&G's impact on dental health has been immense.
The introductions of Crest and later Crest Tartar Control
have helped reduce the average of missing teeth or
cavities in the United States from 15 to three, with more
than 50 percent of children today having no tooth decay.
Our patented pyrophosphate formula (P207) disrupts
tartar formation on the tooth surface. Any calcium that does form is not tightly bound and can be easily removed.
Detergent Detergent
A detergent is a A detergent is a compound, or a compound, or a
mixture of mixture of
compounds, intended compounds, intended
to assist cleaning.
to assist cleaning.
They lower the surface They lower the surface tension of a liquid
tension of a liquid allowing easier allowing easier
spreading and the spreading and the interfacial tension interfacial tension
between two liquids.
between two liquids.
How Does It Work?
How Does It Work?
Soaps and detergents are made from long molecules that Soaps and detergents are made from long molecules that contain a head and tail. These molecules are called
contain a head and tail. These molecules are called
surfactants; the diagram below represents a surfactant surfactants; the diagram below represents a surfactant molecule.
molecule.
The head of the molecule is attracted to water (hydrophilic) The head of the molecule is attracted to water (hydrophilic)
and the tail is attracted to grease and dirt (hydrophobic). When and the tail is attracted to grease and dirt (hydrophobic). When the detergent molecules meet grease on clothes, the tails are the detergent molecules meet grease on clothes, the tails are drawn into the grease but the heads still sit in the water.
drawn into the grease but the heads still sit in the water.
The attractive forces between the head groups and the water The attractive forces between the head groups and the water are so strong that the grease is lifted away from the surface.
are so strong that the grease is lifted away from the surface.
The blob of grease is now completely surrounded by detergent The blob of grease is now completely surrounded by detergent molecules and is broken into smaller pieces which are washed molecules and is broken into smaller pieces which are washed away by the water
away by the water
Anionic Detergent Anionic Detergent
Synthetic detergents have Synthetic detergents have similar molecular
similar molecular
structures and properties structures and properties
as soap. Although the as soap. Although the
cleansing action is similar, cleansing action is similar,
the detergents do not react the detergents do not react
as readily with hard water as readily with hard water
ions of calcium and ions of calcium and
magnesium. Detergent magnesium. Detergent
molecular structures molecular structures
consist of a long consist of a long
hydrocarbon chain and a hydrocarbon chain and a
water soluble ionic group.
water soluble ionic group.
Most detergents have a Most detergents have a negative ionic group and negative ionic group and
are called anionic
are called anionic
Cationic Detergents Cationic Detergents
Another class of Another class of
detergents have a positive detergents have a positive ionic charge and are called ionic charge and are called
"cationic" detergents. In
"cationic" detergents. In addition to being good addition to being good
cleansing agents, they also cleansing agents, they also
possess germicidal possess germicidal
properties which makes properties which makes them useful in hospitals.
them useful in hospitals.
Most of these detergents Most of these detergents
are derivatives of are derivatives of
ammonia.
ammonia.
found in a shampoo or found in a shampoo or clothes "rinse
clothes "rinse
