which type of bonding is most important in ch3ch2ch2ch2ch2ch3

CH₃CH₂CH₂CH₂CH₂CH₃ is normal hexane which only contains C and H only, and since there is not much electronegativity difference between Carbon and Hydrogen, there is hardly any bond polarities. This means that the only attractions between one molecule and its neighbours will be Van der Waals dispersion forces. These will be very small for a molecule like methane, but will increase as the molecules get bigger.