Acidic Polymer‐Assisted Non‐Photochemical Laser‐Induced Crystallization of Potassium Sulfate and Its Morphological Regulation Mechanism

The combination of acidic polymers and non‐photochemical laser‐induced nucleation (NPLIN) is utilized to systematically investigate their regulatory effects on the entire process of potassium sulfate (K 2 SO 4 ) crystallization, from nucleation to crystal growth. Ellipsoidal and needle‐like crystals were obtained, respectively, by adding two acidic polymers, polymaleic acid (PMA) and polyepoxy succinic acid (PESA), into supersaturated K 2 SO 4 solutions under laser irradiation. Subsequent analysis indicated that the selective adsorption of polymers on different crystal faces was the underlying reason for the observed change in crystal morphology. Consistent with this observation, molecular simulation results further confirmed that PMA and PESA exhibit distinct binding energies on different crystal facets, which is the primary factor leading to morphological changes. Within a specific concentration range of PMA, a morphology transition of K 2 SO 4 crystals from ellipsoidal to spherical was observed as the PMA concentration increased. An exponential decay model was established to predict this morphological evolution. In addition, it was found that the presence of acidic polymers significantly reduced the nucleation probability of the crystals in laser‐induced experiments, and the potential underlying mechanisms were explored based on classical nucleation theory.