Soaps and detergents are made from long molecules that contain a head and tail. These molecules are called surfactants; the diagram below represents a surfactant molecule. The head of the molecule is attracted to water (hydrophilic) and the tail is attracted to grease and dirt (hydrophobic).

Starch is an inherently hydrophilic polymer that can easily absorb moisture due to the presence of hydroxyl groups; but this feature weakens its mechanical properties.

Both oxygen and Carbon dioxide are indeed hydrophobic/non-polar molecules and - since they are relatively small - can pass through the plasma membrane. That being said very small hydrophilic molecules like water can also pass through the plasma membrane.

An examination of the hydrophobic nature of lipids deposited on hair surfaces indicates that sebum soil may be cleaned from hair by any of several different detergency mechanisms.

Steroids are overall hydrophobic because of their common tetracyclic hydrocarbon core (Figure ​1G). However, they carry different functional groups at various positions, which influence the orientation and position of the steroid in the membrane (Figure ​1A–F).