Gel storage modulus and hardness

Does hardness test depend on the equilibrium modulus of a gel?

Higher hardness gels have a lower work of adhesion. At high speeds, the work of adhesion becomes almost independent of hardness of the gel suggesting that hardness testing retains more dependence on the equilibrium modulus of the gel at higher speeds than the tack testing.

How do you measure the stiffness of a gel network?

Another useful parameter in characterizing the stiffness of a gel network is hardness. Hardness is measured by indenting a probe into the gel at a specified velocity while measuring the force required for the indentation. The force required to indent the gel to a certain depth is the hardness.

Does gel hardening affect long-term stability in high-temperature and high-salinity environments?

Mechanisms of gel hardening and long-term stability in high-temperature and high-salinity environments were investigated by rheological testing, cryo-scanning electron microscopy (cryo-SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.

What is the mechanism of gel hardening?

The mechanism of gel hardening was investigated in terms of changes in the microstructure of the gels. The networks of gels composed of 1.2 % LCP, 0.8 % HPAM, and 0.2 % crosslinker aged at 130 °C for different times were visualized using cryo-SEM, as shown in Fig. 6. Fig. 6. Cryo-SEM images of DNG after aging at 130 °C for different times.

What is the force required to indent a gel to a certain depth?

The force required to indent the gel to a certain depth is the hardness. While the measured hardness does depend strongly on the modulus of the gel, it also depends on many other measurement parameters such as the size and shape of the gel sample, probe size, speed, and indentation depth.

How to determine the thermal stability of a gel?

The thermal stability of the gel was assessed by determining the dehydration rate, which represents the ratio of the water mass lost from the gel after aging to its initial mass. 2.2.2. Gel molecular structure analysis