Preparation of oriented attapulgite nanofibers using evaporation induced self-assembly

Aligned nanofibers have great application prospects in the field of electron transport and separation. In this work, a nano-attapulgite-based alignment technique was developed. The suspension was prepared from nano attapulgite (ATP), and polystyrene sulfonate sodium (PSS) was introduced to promote the dispersion and stability of ATP. The PSS can adjust the zeta potential of ATP from − 15 to − 50 mV. And the molecular dynamics results also showed that the appropriate PSS can increase the repulsion between ATP by 1.1 × 10⁴ KJ·mol⁻¹. Then ATP layer on the glass substrate was prepared by drop coating and induced evaporation. The results showed that the stability of the suspension played a decisive role in the alignment effect of ATP. ATP would be aligned from the three-phase contact line of air, suspension and substrate, and the width of the alignment interval can reach 1.2 mm, when the content of ATP and PSS was 2 mg·mL⁻¹ and 1 mg·mL⁻¹, respectively. On this basis, an improved alignment technique called “restricted evaporation” was proposed. The three-phase line was pinned many times during the restricted evaporation process, which was beneficial to the alignment of ATP, and the directional alignment interval can be increased to about 20 mm.