•Three azo dyes had been synthesized using N-ethyl substituted, dibromo-substituted and dicyano-substituted phthalimides as diazo components.•Dimer molecular optimization and the interaction energy researching had been done with density functional theory.•Electrostatic force affected the interaction energy of phthalimide-benzene and phthalimide-phthalimide rings most.•Substituent groups mainly altered the dispersion force and reduced the energy of the system.Three azo dyes had been synthesized using N-ethyl substituted, dibromo-substituted and dicyano-substituted phthalimides as diazo components. All of the synthesized intermediates and dyes have been characterized by MS, 1H NMR, IR and elemental analyses. The dyeing behavior and fastness properties of these dyes have been investigated. Modeling the interaction energy of benzene-benzene, phthalimide-benzene and phthalimide-phthalimide rings, molecule optimization and the interaction energy researching have been done with density functional theory ωB97XD, 6-311G++(d,p) basis set. The results showed that: phthalimide molecule has better coplanarity. Molecule energy of benzene-benzene, phthalimide-benzene and phthalimide-phthalimide rings decreased first and then increased with the increase of the distance between the rings, the lowest energy happened when the distance was about 3.5 Å. Electrostatic force affected the interaction energy most. Substituent groups mainly altered the dispersion force and reduced the energy of the system. The optimization interaction energy of phthalimide-phthalimide, phthalimide-benzene and benzene-benzene was −47.78 kJ/mol, −34.66 kJ/mol and −17.59 kJ/mol. Substituted dibromo group reduced the dipole interaction of the dye.Download high-res image (244KB)Download full-size image

In this study, an effective deposition of Ni–P alloy on wool fabric is proposed by a chemical plating approach with PdCl2 solution and a carrier agent chitosan (CTS). CTS possesses strong ability to absorb metal ions through several mechanisms, such as electrostatic attraction and chelation, depending on the pH of the solution. The lowest surface resistance of the wool fabric is achieved when Pd (II) ions are absorbed in acid condition (around pH = 2.5). Sorption isotherms are obtained and modeled using Langmuir and Freundlich model and kinetic curves nicely fitted to the pseudo-first-order equation. Also, isotherms have been introduced to obtain the thermodynamic parameters, such as Gibbs free energy, enthalpy and entropy. The resulting positive value of the enthalpy indicates that the adsorption is an endothermic process. Conductive wool fabrics are characterized by scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR) spectroscopy. Evidenced by SEM, CTS–Pd is found on the surface of fabrics and effectively activated the chemical plating. FT-IR shows the adsorption of Pd (II) ions on CTS is mainly controlled by physical adsorption. Mechanical and physical tests were investigated and the encouraging results show no significant modification and open new perspectives for future application of wool fabrics.Research highlights▶ An effective chemical plating of Ni–P alloy on wool fabrics is proposed. ▶ Chitosan (CTS) is used as a carrier agent to absorb catalyst PdCl2. ▶ Adsorption mechanism of Pd (II) ions on CTS is studied and kinetic curves nicely fitted to the pseudo-first-order equation. ▶ Conductive wool fabrics are also characterized and have a good ability of electromagnetic shielding.