Dynamics and Microstructure Formation during Nucleation of Lysozyme Solutions

The liquid−liquid coexistence region of aqueous lysozyme−NaCl solutions was examined by time-resolved small-angle static light scattering and light microscopy. At the initial stages of the reaction scattered intensities peaked at finite scattering vectors as expected for globular domains growing under the influence of competing interactions. An oscillatory behavior of the mean domain radius is observed at later stages of the reaction as a function of time. Microscopic observations revealed domains undergoing correlated ripening with time and forming labyrinthine microstructure and microcrystals at later stages. Potentials of the mean force computations yield first qualitative insights into the effective pair interactions during the process. The behavior of the system can be understood qualitatively as spinodal decomposition followed by nucleation, leading to a modulated phase type of microstructure.