This talk will present how to fabricate stimuli responsive materials by blending commodity elastomers with simple molecular crystals, such as fatty acids and parafin waxes. Two examples will be shown. In the first example, natural rubber is swollen with a fatty acid to generate a second, thermally reversible load-bearing network. This results in a shape memory polymer with high fixity and recovery. The relationship between the bulk shape memory behavior and the fatty acid crystal network will be discussed. In the second example, parafin wax is used as an internal dilating agent to swell a thermoplastic elastomer. When bonded to another polymer film, the strain mismatch generate bending motion, which can be used a thermally responsive actuator