Salicylic acid the OH group is "ortho" to the carboxyl group. It is also known as 2-hydroxybenzoic acid. It is poorly soluble in water (2 g/L at 20 °C). Aspirin (acetylsalicylic acid or ASA) can be prepared by the esterification of the phenolic hydroxyl group of salicylic acid with the acetyl group from acetic anhydride or acetyl chloride. Salicylic acid can also be prepared using the Kolbe-Schmitt reaction. Salicylic acid is used as a food preservative, a bactericidal and an antiseptic. Sodium salicylate is a useful phosphor in the vacuum ultraviolet spectral range, with nearly flat quantum efficiency for wavelengths between 10
Polyacrylic acid of PAA have been prepared that are responsive to pH and temperature stimuli, demonstrating the possibility to be used for drug delivery purposes. ATRP has been used to growth PAA brushes from the surface. One reported approach was with surface-initiated ATRP of tert-butyl acrylate that was subsequently deprotected through pyrolysis to form the carboxylic acid. These PAA brushes can form chelate complex with silver and can therefore exhibit antibacterial activity. Polyacrylic acid Poly(acrylic acid) (PAA; trade name Carbomer) is a synthetic high-molecular weight polymers of acrylic acid. The IUPAC name is poly(1-carboxyethylene. They may be homopolymers of acrylic acid, or