Methods of adjusting the mechanical properties of a polymeric material may include forming a polymer network having a plurality of permanent cross-links and coupled to a plurality of reversible cross-links, wherein the polymer network has a shear storage modulus of greater than about 4×104 Pa; and heating the polymer network using a heat source to dissociate the reversible cross-links, wherein heating the polymer network reduces the shear storage modulus to less than about 4×104 Pa. In some embodiments, a polymeric material may include a polymer network comprising a plurality of permanent cross-links and coupled to a plurality of reversible cross-links that are dissociable with the application of a stimulus and associable with the removal of the stimulus, wherein the shear storage modulus of the polymer network is less than about 4×104 Pa in the presence of the stimulus and greater than about 4×104 Pa in the absence of the stimulus.