An important step in understanding molecular assembled systems is to examine the structure and physical properties at various length scales and clarify the correlation between them. However

while the structures of these systems have been extensively studied from nanoscopic to macroscopic scales

their viscoelastic properties have been often limited to bulk rheological measurements. By using optical tweezers and particle tracking

we here show the local viscoelastic properties and their spatial distributions for the following systems: worm-like micelle solution

supramolecular hydrogel and lyotropic liquid crystal

which are formed by self-assembly of amphiphilic molecules in water. We found that all systems studied possessed a spatial heterogeneity in their viscoelastic properties and this was originated from the heterogeneous structures. It is interesting to note that there is the heterogeneity with the characteristic length scale of sub-micrometer or micrometer scale

thereby structures

although the systems are formed by molecules with nanometer size. The findings of these studies should lead to a better understanding of the dynamics of such systems.