Comparing microscopic with macroscopic elastic properties of polymer gel

Measurements of the local elastic modulus of agar gels obtained with atomic force microscope (AFM) force mapping were compared with values obtained by the tensile creep method. The observed spatial distributions of the local elastic modulus over the gel surface in AFM elastic images clearly corresponded to the network structure of agar fibers observed both in AFM topographic and scanning electron microscope (SEM) images. Both peak and average values of distribution functions in the histograms of local elastic modulus increase monotonically with the agar concentration. Values obtained by AFM force mapping were found to be proportional to values obtained from creep experiments.