This study investigates the influence of carbon nanotube sponges (CNT-sponges) at concentrations of 0.1, 0.3, and 0.5 wt% on the rheological behavior of three series of poly(styrene-co-acrylonitrile) [P(S:AN)] polymer solutions. Amplitude and frequency sweep tests were performed to evaluate the Linear Viscoelastic Range (LVER), storage modulus (G'), loss modulus (G''), loss factor (tan δ), structural behavior, and overall homogeneity of the composite solutions. The rheological measurements revealed a viscosity range between 0.8 and 20 Pa·s across all samples. The loss factor analysis indicated a liquid-like viscoelastic response for solutions containing 0.1 and 0.3 wt% CNT-sponges, while the 0.5 wt% formulation exhibited a solid-like response, suggesting increased elasticity and network formation at higher CNT concentrations.

These rheological insights are critical for predicting the electrospinnability of the solutions, as viscoelastic behavior significantly influences fiber formation. To validate the suitability of each formulation for electrospinning, all solutions were processed using a standard electrospinning setup. The resulting nanofibers were characterized by scanning electron microscopy (SEM) to assess morphology, fiber continuity, and uniformity.

The findings confirm that rheological evaluation can effectively guide the formulation of electrospinnable composite solutions. Specifically, a CNT content of 0.3 wt% was identified as optimal for achieving balanced flow behavior and fiber quality, highlighting its potential for advanced fiber-based applications.