Kinetics of stochastic degradation∕evaporation processes in nanoparticle aggregates and polymerlike systems with multiple bonds

Using the graph representation of stochastic degradation/evaporation processes, general solutions of kinetic rate equations are found and analyzed, describing degradation of complex systems with multiple bonds, such as particle aggregates, fractals, self-arranged systems, double-stranded polymers and polymer networks, biological molecules, etc. The analysis is conducted on the example of thermal fragmentation of aerosol nanoparticles, caused by stochastic evaporation of bonding volatile molecules. A simple analytical approach for the determination of numbers of particles at different degradation stages, undertaking different evolutionary paths is developed and applied for the analysis of several specific types of aerosol particle aggregates. Significant probabilistic delays are shown to occur during degradation/fragmentation of intermediate modes, resulting in accumulation of particles in these modes. Conditions for such accumulation are determined and discussed. The obtained results are immediately applicable for the analysis of any other polymer-like systems with multiple bonds experiencing stochastic degradation