hydrophobic

Examples of hydrophobic in the following topics:

• Hydrophilic and Hydrophobic Colloids

  • Hydrocolloids are stable suspensions of hydrophilic molecules; emulsions are suspensions of hydrophobic molecules that need stabilization.
  • A hydrophobic colloid, or emulsion, is defined as a colloid system where the particles are hydrophobic polymers.
  • Since the colloid does not interact with the aqueous solvent, hydrophobic colloids are inherently unstable and generally do not form spontaneously.

• Salt Formation

  • Carboxylic acids and salts having alkyl chains longer than six carbons exhibit unusual behavior in water due to the presence of both hydrophilic (CO2) and hydrophobic (alkyl) regions in the same molecule.

• Soaps & Detergents

  • Carboxylic acids and salts having alkyl chains longer than eight carbons exhibit unusual behavior in water due to the presence of both hydrophilic (CO2) and hydrophobic (alkyl) regions in the same molecule.
  • By gathering the hydrophobic chains together in the center of the micelle, disruption of the hydrogen bonded structure of liquid water is minimized, and the polar head groups extend into the surrounding water where they participate in hydrogen bonding.
  • Micelles are able to encapsulate nonpolar substances such as grease within their hydrophobic center, and thus solubilize it so it is removed with the wash water.

• Types of Synthetic Organic Polymers

  • This makes them hydrophobic, meaning they do not readily absorb water; this is a useful trait, as the alternative—imagine a water bottle that becomes soggy when filled with water, for instance—might be disastrous.
  • PTFE is hydrophobic: neither water nor water-containing substances can interact with PTFE.
  • Teflon (PTFE) is often used to coat non-stick frying pans as it is hydrophobic and possesses fairly high heat resistance.

• Water Solubility

  • A common nomenclature used to describe molecules and regions within molecules is hydrophilic for polar, hydrogen bonding moieties and hydrophobic for nonpolar species.

• Carboxylic Acids

  • Carboxylic acids are polar molecules; they tend to be soluble in water, but as the alkyl chain gets longer, their solubility decreases due to the increasing hydrophobic nature of the carbon chain.

• Phospholipids

  • As shown in the following diagram, the polar head groups on the faces of the bilayer contact water, and the hydrophobic alkyl chains form a nonpolar interior.

• Amines

  • However, the solubility decreases with an increase in carbon atoms, due to the increased hydrophobicity of the compound as the chain length increases.

• Secondary & Tertiary Structure of Large Peptides and Proteins

  • These include hydrophobic attraction of nonpolar side chains in contact regions of the subunits, electrostatic interactions between ionic groups of opposite charge: hydrogen bonds between polar groups; and disulfide bonds.

• Allotropes of Carbon

  • The surface of diamond is lipophillic and hydrophobic, which means it cannot get wet by water but can be in oil.