Novel super-flexible resorcinol-formaldehyde (RF) aerogels were synthesized via a sol-gel process followed by supercritical drying. These aerogels are soft and are reversibly deformable up to 25%. Low density of 0.06 g cm(-3) and low Young's modulus of about 116 kPa distinguish these sponge-like aerogels from conventional RF-aerogels made especially by ambient drying. The synthesis occurs from a very diluted sol-solution and demands high accuracy during preparation. Formation of small particles and relatively big pores allow bending of pore walls without breaking and establish microstructural conditions of flexibility. The experiments show the microstructure formation leading to superflexible RF-aerogels is a very sensitive process and depends on the homogeneity of the sol and its pH value. Shrinkage during for instance ambient dyring induces a collapse of the pore structure and reduces flexibility. Additionally, a definition and calculation of the term "flexibility" is presented and discussed in this study. (C) 2015 Elsevier B.V. All rights reserved.