Effect of Acidic Polymers and Impurity Microparticles on CuSO4 Nucleation via Nonphotochemical Laser Induced Nucleation

Abstract

Crystal morphology in supersaturated copper sulfate (CuSO₄) solutions in the presence of acidic polymers is investigated using the non-photochemical laser-induced nucleation (NPLIN) technique. The solubility of copper sulfate in different solvents is measured using the continuous addition method, which is detailed in the Supporting Information. The optimum range of laser power is selected based on a suitable nucleation probability and desirable crystalline morphology. Two different forms of copper sulfate crystals are obtained by a nanosecond pulsed laser with the wavelength of 532 nm. The experimental results show that the addition of impurities increases the probability of nucleation of copper sulfate crystals during nanosecond laser pulse irradiation, which is consistent with the nanoparticle heating mechanism for NPLIN; the addition of acidic polymer can control crystal growth rate of each crystal surface. All CuSO₄ crystals obtained from the technique of NPLIN are revealed as copper sulfate pentahydrate (CuSO₄·5H₂O) through powder X-ray diffraction analysis. After the sample solution is added with polyacrylic acid, the crystalline morphology changes from polyhedral 3D morphology to long rod morphology. Based on this, different kinds of impurities and acidic polymers are applied in order to achieve a controllable approach on nucleation probability and crystalline morphology of CuSO₄·5H₂O crystals. The effects of impurities and acidic polymers on crystals are analyzed to study the underlying mechanism of NPLIN and morphological differences.