Dimethyl Sulfoxide and Sodium Chloride Modulate the Crystal Structure in PMIA to Enhance Dyeing Performance: Molecular Dynamics Simulation and Experimental Investigations.

The widespread use of meta-aramid (PMIA) is limited by its poor dyeing performance, and researchers often struggle to qualitatively and quantitatively assess its microscopic structural regulation when attempting to improve dyeing performance. Herein, DMSO/NaCl is chosen to synergistically modulate the structure of PMIA to improve its dyeing properties in combination with experiments and simulations. Initially, characterization and color testing reveal that the DMSO/NaCl combination induces structural changes in the amorphous regions of the PMIA fiber, improving the dispersion of the dye solution. Notably, PMIA exhibited a significant improvement in dyeing performance, with the K/S value increasing from 2.6 to 16.0 and dye uptake rising from 20.4% to 73.2%, while maintaining excellent colorfastness and mechanical integrity. Molecular dynamics simulations further confirm that DMSO/NaCl disrupts the hydrogen bonding network in the amorphous regions of PMIA, enhancing the mobility of molecular chains and increasing the free volume, thus providing additional adsorption and binding sites for the dye molecules. These findings highlight the potential of combining experimental and computational approaches to optimize the structural regulation and dyeing performance of PMIA fibers.