Poly(vinyl alcohol) nanocomposite films containing chemically exfoliated molybdenum disulfide

Molybdenum disulfide (2H-MoS₂) was exfoliated in water after reaction with n-butyl-lithium. Using either alkaline or neutral conditions, different amounts of the resulting single-layer suspension were employed as filler for the production of poly(vinyl alcohol) films containing distinct disulfide contents. These nanocomposite films were obtained by wet casting and were further characterized by powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) and Raman spectroscopies. The mechanical properties of the films were also evaluated. Characterization studies revealed the attainment of homogeneous nanocomposite films in both alkaline and neutral conditions, indicating good distribution and interaction of the hydrophilic filler with the polyhydroxylated polymer. Improved Young's (tensile) modulus (+57%) and tensile strength (+9%) as well as reduced elongation (−78%) were achieved only when the neutral suspension of single layers was utilized. Increased MoS₂ content diminished the crystallinity of the polymer, while enhanced mechanical properties were obtained in the presence of intermediate filler content (around 1 wt%).