Surface Chemistry an der TU Dresden

hydrogel undergoes attractive interactions with and swell in water, but does not dissolve completely because of crosslinking 

hydrophilic polymers dissolve in water

- control adsorption

- improve blood compatibility 

- improve lubricity

- improve wear and corrosion resistance

The stronger the intermolecular forces inside of the condensed phase (cohesion) the larger are the values of surface tension.

--> the cohesion of water is stronger (H-bonds) than that of heptane and so is the surface tension

- help understanding how atoms/molecules organize in liquids and solids

- + their targeted modifications are our tool to design tailored biomaterials

Intermolecular forces happen between molecules/ions/atoms and a surface

--> weak compared to intramolecular forces

--> collectively strong

charge-charge

charge-dipole

dipole-dipole

induced dipole-dipole

induced dipole-induced dipole

vdW repulsion

dipole-dipole = Keesom

dipole-induced dipole = Debye

induced dipole-induced dipole = London

electrostatic interactions: charge-charge/ion-ion, charge-dipole

van der Waals interactions: dipole-dipole, induced dipole-dipole, induced dipole-induced dipole, vdW repulsion

cohesion forces > adhesion forces (molecules of one surface being more attracted to each other than to the other surface)

surface tension: defines adhesion, adsorption, absorption, wetting

by measuring the contact angle 

this methods help determine the critical surface tension of solids by adding liquids with different known surface tensions, if liquid wets solid completely (cos a = 1) --> critical surface tension