Microdomain structure of agar gels observed by mechanical-scanning probe microscopy

The inhomogeneous structure of agar gels was examined by means of mechanical-scanning probe microscopy. Several domains were observed in the elasticity images, while such domains could not be seen in the height images. The domain size decreased with increases in agar concentration. We found that the histograms of the logarithm of the local elastic modulus were described well by a single normal distribution. As the agar concentration increased, the peak values of the histograms increased, while the half-value width remained constant. These results imply that the gelation process of agar gels has a common mechanism, despite its complexity.