While two fatty acids can self-associate via hydrophobic attraction of the alkyl groups in water, the association is strengthened due to additional H-bonding interaction with each other, either directly or indirectly via H-boding interaction with water. The carboxylic acid groups can also deprotonate thus forming carboxylate ion, which can also form various types of H-bonds with water or with another proton donating group. The ether group of a non-ionic surfactant can also engage in an H-bonding interaction with the protons of water or the carboxylic acid.