text: Dipalmitoylphosphatidylcholine (DPPC) is a phospholipid with two 16-carbon saturated chains and a phosphate group with quaternary amine group attached. The DPPC is the strongest surfactant molecule in the pulmonary surfactant mixture. It also has a higher compaction capacity than the other phospholipids, because the apolar tail is less bent. Nevertheless, without the other substances of the pulmonary surfactant mixture, the DPPCs adsorption kinetics is very slow. This happens primarily because the phase transition temperature between gel to liquid crystal of pure DPPC is  41.5 °C, which is higher than the human bodys temperature of 37 °C.