The use of 3D printing to create prototypes and devices from elastomeric and polymeric materials has appended the design functionality for new materials including uses in biomedical devices enabling rapid development While 3D printed polymers can be further classified into thermoplastics, thermosets, and elastomers based on their thermo-mechanical properties. The processability and functionality of rubbers and elastomers make it a challenge to employ 3D printing methods for additive manufacturing. The transition to a final phase or cross-linked structure results in new properties in combination with the processing method. This is more evident with the choices of 3D printing methodologies (FDM, SLA, SLS, VSP) which can make use of blended or formulated compositions.  We have demonstrated the 3D printing of biomedical grade thermopolastic polyurethanes (TPU), silicones, and rubberized epoxies. However, 4D printing allows the design of new materials and applications based on integrating the chemistry of conversion with the printing mode. In this talk, we demonstrate the fabrication of concept objects and elastomeric actuators based on the use of biomedical grade TPU melts and extruded viscous solutions. The result is an extrudable precursor and nancomposite elastomers which can be printed via viscous extrusion printing (VEP) or VSP and then converted to an elastomeric actuating materials with very high cyclic compressibility. Other work based on the use of SLA, SLS, FDM, towards high strength silicones and nanocomposite materials will be discussed.