The existing theoretical model relating shear modulus to inter-particle interaction potential always significantly overestimates the modulus compared with its experimental value for colloidal crystal formed by highly-charged particles. We suppose that such huge disagreements between the theoretical and experimental results are due to that the theoretical model is derived from perfect crystalline structures. To modify the theoretical model, the effect of void defects is introduced to the model and the Sogami-Ise potential model is adopted instead of the commonly used Yukawa potential model. It is shown that with these two modifications the shear modulus model produces results much more consistent with the experimental ones.
Wang LW(王林伟). Effect of void structures in crystalline structure on the shear moduli of charged colloidal crystals[J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects,2017,516:115-120.