Book excerpt: "Aerogels are three dimensional highly porous solid objects that provide density reduction compared to dense objects. Those materials can have applications in different classes of energy storage and the two types that are focused in this dissertation are mechanical energy and thermal energy storage. Shape memory materials can store and recover elastic deformation energy when triggered by an external stimulus such as temperature. To incorporate those properties, shape memory polymeric aerogels (SMPA) were synthesized from a rigid isocyanurate containing triisocyanate (N3300 A) and four short oligomeric derivatives of ethylene glycol: H(OCH2CH2)[sub n]OH (1 d"n d"4). The shape memory effect (SME) of those aerogels were evaluated via four figures of merit namely strain fixity, strain recovery, strain recovery rate and fill factor. The morphologies of skeletal frameworks of those aerogels varied from micrometer sized particles with thick necks to bicontinuous structures, that are typical of spinodal decomposition. A Marcus-type thermodynamic-kinetic relationship was identified between that shape recovery rate, R[sub t](N), and the elastic modulus, E. Other part of the dissertation deals with the synthesis of nanoporous metallic iron (Fe(0)) aerogels via carbothermal reduction of interpenetrating networks of polybenzoxazine and iron oxide nanoparticles. Excess carbon was removed oxidatively at 600 °C under flowing air and the oxides of Fe(0) thus produced in the oxidative step were reduced back to Fe(0) with H2 at different temperatures ranging from 300 - 1300 °C. Those final monoliths were loaded with perchlorates and ignited with a flame in open air. Based on the temperature of the reduction step, monoliths either fizzled out (d"00 °C), exploded violently (500-900 °C), or behaved as thermites (e"50 °C)"--Abstract, page v.