1：Experimental Design and Method Selection:

The study employed nonlinear dielectric effect (NDE) measurements, near-infrared (NIR) spectroscopy, and density functional theory (DFT) calculations to investigate hydrogen bonding and association phenomena in 1-hexanol/n-hexane mixtures across the entire mole fraction range (0 to 1 with a step of 0.1). A modified Ma?ecki's model was used for interpreting dielectric data, incorporating thermodynamic equilibrium constants and activity coefficients.

2：1). A modified Ma?ecki's model was used for interpreting dielectric data, incorporating thermodynamic equilibrium constants and activity coefficients. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Mixtures were prepared gravimetrically using distilled 1-hexanol (98% ACROS Organics) and n-hexane (95+% ACROS Organics), dried over molecular sieves 3A. The same samples were used for all measurements.

3：3A. The same samples were used for all measurements. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included a Nicolet Magna 860 spectrometer with DTGS detector for NIR spectroscopy, a custom-built NDE setup with LC resonance circuit and capacitor, a PAAR 4001 densitometer, and an Abbé refractometer. Materials were 1-hexanol and n-hexane from ACROS Organics.

4：Experimental Procedures and Operational Workflow:

NIR spectra were recorded from 4000 to 10000 cm?1 at 4 cm?1 resolution with 128 scans in a 5 mm quartz cell at 25°C. NDE measurements involved applying a strong electric field (up to 9·10? V/m) and measuring permittivity changes. Density and refractive index were measured with specified precisions. DFT calculations were performed at B3LYP/6-311++G(d,p) level using Gaussian

5：Data Analysis Methods:

Data were analyzed using curve-fitting for NIR spectra (Gaussian and Lorentzian functions) and numerical fitting for dielectric data to obtain populations of associates, with errors estimated for parameters.