1：Experimental Design and Method Selection:

The study involved synthesizing a soluble polyimide (6FDA-TFDB) through polycondensation and selecting four solvents (DMAc, NMP, DMF, DMSO) with varying solubility parameters. Rheological measurements were used to establish power law relationships between specific viscosity and concentration, applying Zimm, Rouse-Zimm, and Doi-Edwards models for different concentration regions (dilute, semidilute unentangled, semidilute entangled).

2：Sample Selection and Data Sources:

The polyimide sample was synthesized and fractionated to obtain a narrow polydispersity index. Solutions were prepared in the selected solvents at various concentrations (0-220 mg/mL) and temperatures (20-45°C). Data were collected from rheological flow curves and viscosity measurements.

3：List of Experimental Equipment and Materials:

Equipment included a DHR-2 stress-controlled rheometer (TA Instruments), FTIR spectrometer (Brucker Vertex 70), NMR spectrometer (Brucker AV400), and SEC system with multidetectors (Waters and Wyatt Technologies). Materials included TFDB, 6FDA, DMAc, DMSO, DMF, NMP, TBAB, and other chemicals from suppliers like Sigma-Aldrich and Xilong Chemical.

4：Experimental Procedures and Operational Workflow:

The polyimide was synthesized via chemical imidization, fractionated using THF/water, and characterized by FTIR, NMR, and SEC. Rheological measurements were performed using a cone-plate geometry to obtain zero-shear viscosity and specific viscosity vs. concentration curves. Temperature was controlled using a Peltier plate.

5：Data Analysis Methods:

Power law exponents were determined from log-log plots of specific viscosity vs. concentration. Critical concentrations (overlap and entanglement) were identified from these plots. Data were analyzed using theoretical models (Zimm, Rouse-Zimm, Doi-Edwards) and statistical methods for error estimation.