Cercignani conjecture is true for Smoluchowski coagulation equation

In the present study, the information entropy for smoluchowski coagulation equation is proposed based on the statistical physics. and the normalized particle size distribution is a log-normal function at equilibrium from the principle of maximum entropy and moment constraint. the parameters in the particle size distribution are determined as simple constants, the result reveals that the assumption that algebraic mean volume be unit in self-preserving hypothesis is reasonable. based on the present definition of the information entropy, the cercignani conjecture holds naturally for smoluchowski coagulation equation. Together with the fact that the conjecture is also true for Boltzmann equation, cercignani conjecture holds for any two-body collision systems, which will benefit the understanding of Brownian motion and molecule kinematic theory, such as the stability of the dissipative system, and the mathematical theory of convergence to thermodynamic equilibrium.