Spraying Polypyrrole Coatings on Alginate Nonwoven Fabrics and Investigating Their Conductive and Photothermal Properties

In this paper, a polypyrrole (PPy) dispersion was prepared by a chemical oxidative polymerization method, and then, the PPy coatings were constructed on alginate nonwoven fabrics (ANFs) via a direct spraying method. By FTIR, XPS, SEM, and EDS characterizations, it was confirmed that successful polymerization and homogeneous adhesion of PPy on ANFs occurred. The influences of Py dosage on the electrical conductivity, wettability, and photothermal conversion of the PPy-coated ANFs (PPy/ANFs) were investigated. Moreover, the solar-driven water evaporation performance of the PPy/ANFs was investigated, and it was found that with a Py dosage of 0.3 mol m –2, a water evaporation rate of 1.73 kg m –2 h –1 and a solar–thermal energy conversion efficiency of 93.54% under 1 sun could be achieved. Finally, the evaporation performance of the PPy/ANFs for water containing different colorants (dyes and pigments) was researched. For soluble dyes, cationic methylene blue (MB) had a weaker inhibition of water evaporation than anionic methyl orange (MO), mainly due to its stronger electrical attraction to ANFs. For insoluble PG7 pigment dispersed by different surfactants, the one stabilized by cationic DTAC had smaller adverse effects on the water evaporation rate of the PPy/ANFs. This could be attributed to its stronger electrostatic attraction to ANFs and larger particle size than those of SDS, thereby reducing the suppression of water evaporation. This study provided a facile strategy for fabricating flexible PPy-functionalized ANFs and offered insights into the efficient solar-driven treatment of water containing colorants.