1. Thermotropic LC’s – A Reminder

2. Lyotropic Liquid Crystals Molecules usually amphiphilic – hydrophobic and hydrophilic parts. How will these behave around water? Hydrophilic head Hydrophobic tail

3. Interaction With Water Orientational order induced by addition of solvent. Hydrophilic heads of the molecules are attracted to the water. What will the hydrophobic tails be attracted to? What shapes may form?

4. One option… The exact shape formed will depend on the concentration and temperature.

5. Lyotropic Liquid Crystal Phases

6. Lyotropic LC’s in Nature Common in biological systems e.g. cell membranes.

7. How About Bubbles Soap bubbles are made of surfactants (amphiphilic) and water. How do the water and surfactants arrange themselves in a bubble?

8. What About Colour? Light can reflect on the inner or the outer bubble surface. Reflected light can interact constructively or destructively. http://www.webexhibits.org/ca usesofcolor/15E.html

9. More on Colour The observed colour depends on thickness. Where is the soap mixture the thinnest?