AFM experiments reveal that increasing temperature induces melting of LE and LC domains, decreasing their sizes (see Supporting Information for details, Figure ). In our simulations, both S400 and L3200 systems are studied at three additional temperatures, 𝑇 𝑟𝑒𝑎𝑙 = 304𝐾, 313𝐾, and 324𝐾 (𝑇 𝐷𝑃𝐷 = 0.7, 0.75 and 0.8 respectively), although only a few large systems are simulated due to computational limitations. Figure depicts the behavior of LE and LC phases with temperature in the L3200 systems at 𝑎 𝐿 = 64.6 ± 0.13 𝐴 𝑜 2 . The reported uncertainty in the area per lipid (aL ± 0.13 Å²) reflects the statistical variation observed across monolayers at four different temperatures (293K, 304K, 313K, and 324K), providing a measure of thermal effects on molecular packing. Figure provides an excellent demonstration of the monolayer behavior upon temperature change in terms of tail order and thickness parameters. The large LC and LE domains melt between 293 K and 304 K, which is still below the transition temperature of DPPC, 314 K. It is interesting to note that as the temperature 16 increases, both blue regions, where lipids orient parallel to the interface as well as the red regions, where the lipids orient normal to the interface, diminish (Figure ). The blue region is the lowest lipid density phase where a lipids occupies most interfacial area and the formation of holes or a gas phase can occur when the lipids are parallel to the interface. The temperature 293 K is also close to the suggested triple point of DPPC monolayers at 290 K, where the gas, LE and LC phases coexist. Thus, increase in temperature not only decreases order in the LC phase, but also increases the order in the LE phase. This is also clearly evident in the snapshots at 313 K, which is close to the critical point, and at 324 K, which is well above the critical point. These snapshots show that the LE and LC phases have become mixed.