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Abstract
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Molecular design plays a crucial role in the development of cation exchange membranes (CEMs) for membrane
brine electrolysis (MBE) processes. This study addressed key challenges affect the membrane micro-level
structure and performance in MBEs. Considering the most prevalent, harsh conditions, saturated hydrated
state, and diffusion of sodium ions, we explore molecular dynamics (MD) simulations study alongside experimental validation of heterogeneous sulfonated poly (styrene-co-divinylbenzene) SPS-DVB-based CEMs for MBEs.
To assess the saturated hydration level (λ), the interactions of sulfonic groups with water molecules were
determined. Both simulation and experimental results revealed λ = 3. Also, the quantified structural characteristics were evaluated. Then, the degree of sulfonation (DS) of 60 % was found optimal, resulting in synchronized sodium diffusivity, thermal stability and mechanical properties (5×10− 7 cm2.s− 1, 389 K, 3.26 GPa, respectively). Upon specifying proper parameters, due to the heterogeneous structure of SPS-DVB, further simulations were implemented to assess the optimal composition ratio of SPS-DVB to polyvinylidene fluoride (SPSDVB: PVDF) at varied ratios of (10,90, 30,70, 50,50, 70,30, 90:10) at 353.15 K and 1 bar. The mechanical
properties, chemical, and thermal stability of the SPS-DVB: PVDF membranes significantly improved SPS-DVB
loading at 70 wt%. As a result, the ratio of 70:30 was the optimum value based on the sodium ion conductivity (6.1 mS.cm− 1), closely matching experimental results (6.71 mS.cm− 1). Therefore, MD simulations and
experimental results collectively highlight the potential of SPS-DVB- based CEMs as promising candidates for
MBEs, offering significant insights into molecular design and optimization.
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