Thermoplastic elastomers(TPEs)are generally entropic networks with micro-phase separated morphology.They are made of flexible chain segments which impart elastic properties and physical crosslinks which connect flexible chain segments together upon acting as knots.One prominent weakness of TPEs is the lower elasticity and higher permanent set compared to rubbers(thermosets),because the physical interactions among physical crosslinks are relatively weak and easily be broken under external stresses.Many attempts have been made to further strengthen physical interactions so as to reduce permanent set.However,physical interactions remain inherently weak.Here,we report when a nonplanar moiety is introduced into polyurethane backbone,the polyurethane demonstrates super elasticity and low permanent set.Molecular dynamics simulations and single molecule force spectroscopy show that nonplanar structures such as cycloaliphatic rings are acting as 'molecular springs' which are capable of undergoing chair-to-boat conformational transition under stress and fully reversible after releasing the force.Thermoplastic polyurethane(TPU)elastomers with appropriate molecular springs can be 99% recoverable after a large deformation of 760% whereas controlled ones are only 76%.Our results provide molecular-design guidelines for polymers responding to external stress by enthalpy elasticity.