Proton Permeability Measurements of Dendronized PECH-co-EO Membranes Using an Orion 4-Star pH/ISE Multimeter

The uploaded dataset includes proton permeability measurements for the membranes CP41, CP71, CP0, and Nafion, evaluated using a two-compartment Teflon diffusion cell. The setup consists of a feed and a stripping compartment separated by the tested membrane. Each membrane sample was mounted to give an effective membrane area of 0.66 cm², with 200 mL of solution in each compartment. All experiments were performed at ambient temperature (≈25 °C). During each experiment, the pH of the stripping solution was monitored every 10 seconds using an Orion 4-Star pH/ISE Multimeter (Thermo Fisher Scientific). For proton transport tests, the feed compartment contained a 0.1 M HCl aqueous solution, while the stripping compartment contained a 0.1 M aqueous solution of LiCl, NaCl, or KCl, depending on the experiment. Proton permeability was determined based on time-resolved changes in the stripping solution, applying the standard transport equations described below. The permeability coefficient ppp (cm s⁻¹) was calculated according to: −ln⁡(CfC0)=A pVf t-\ln\left(\frac{C_f}{C_0}\right) = \frac{A\,p}{V_f}\,t−ln(C0Cf)=VfApt where C0C_0C0 (mol L⁻¹): initial feed concentration CfC_fCf (mol L⁻¹): feed concentration derived from stripping concentration at time ttt VfV_fVf (mL): feed volume AAA (cm²): membrane area The feed concentration was obtained using: Cf=C0−CsC_f = C_0 - C_sCf=C0−Cs with CsC_sCs being the stripping concentration. Under steady-state conditions, proton flux JJJ (mol cm⁻² s⁻¹) was calculated using Fick’s First Law: J=P ΔClJ = \frac{P\,\Delta C}{l}J=lPΔC where PPP (cm² s⁻¹): permeability lll (cm): membrane thickness ΔC\Delta CΔC: concentration difference between feed and stripping solutions Because C0≫CsC_0 \gg C_sC0≫Cs, it was assumed that ΔC≈C0\Delta C \approx C_0ΔC≈C0. The permeability was related to the permeability coefficient by: P=p lP = p\,lP=pl and flux by: J=p C0.J = p\,C_0.J=pC0. For proton transport analysis, data were fitted according to the model above using the time window of 15–120 h, ensuring capture of the long-term diffusion regime. These measurements provide quantitative insight into proton transport behavior, membrane selectivity, and long-term permeability characteristics for the tested ion-exchange membranes. References Membrane compositions:M. et al., Polymers, 2021. DOI: 10.3390/polym13223915