Mesoscale Simulation on the Hydrated Morphologies of SPEEK Membrane

Abstract

Proton transport in proton exchange membrane is considered to depend on the hydrophilic domain formed by the microphase separation between hydrophobic and hydrophilic segments of the membrane. Therefore, the study of hydrated morphologies is crucial to understand proton transport. Here, the mesoscopic structure of sulfonated polyether ether ketone (SPEEK) membrane and SPEEK/polyethersulfone (PES) blend membrane is investigated by dissipative particle dynamics (DPD) simulation. The degree of sulfonation, water content, and PES content are considered to affect proton transport. Results show that the hydrophilic particles combine with water and are separated from hydrophobic particles to form clusters of different sizes. For the SPEEK membrane, with the increase in the sulfonation degree, clusters become large and begin to connect. Compared with isolated clusters at low water content, water clusters become large with increased water content. When water content λ = 16, the cluster size is the largest. The addition of PES accelerates the phase separation in the membrane and increases the size of water clusters. When SPEEK/PES = 4:6, the cluster size is the largest and provides the best proton transport pathway.

Coarse-Grained Modeling of Ion-Containing Polymers

“…Wang et al performed DPD simulations to investigate the effects of adding poly(ether sulfone) (PES) to sPEEK. 182 Their results demonstrate that the addition of PES facilitates the nanophase separation and the formation of larger water-containing clusters. The optimal ratio of sPEEK/PES was found to be 4:6, for which the largest water channels form to improve the transport of water and protons.…”

“…Another direction for improving microphase separation is to blend sPEEK-type ionomers with other polymers. Wang et al performed DPD simulations to investigate the effects of adding poly­(ether sulfone) (PES) to sPEEK . Their results demonstrate that the addition of PES facilitates the nanophase separation and the formation of larger water-containing clusters.…”

“…Their results demonstrate that the addition of PES facilitates the nanophase separation and the formation of larger water-containing clusters. The optimal ratio of sPEEK/PES was found to be 4:6, for which the largest water channels form to improve the transport of water and protons . Recently, Ma et al performed DPD simulations to study the compatibility between sPEEK and PVDF polymers.…”

Mesoscale hydrated morphology of perfluorosulfonic acid membranes

“…Dissipative particle dynamics (DPD) is an outstanding representative of mesoscale simulation that plays an important role in the study of PEM. [29][30][31] DPD was proposed by Hoogerbrugge and Koelman 32 in 1992 and further improved by Espanol and Warren 33 in 1995. The motion of particles was controlled by Newton's motion equation.…”

“…Mesoscale simulation is a gradually emerging method to tackle this issue. Dissipative particle dynamics (DPD) is an outstanding representative of mesoscale simulation that plays an important role in the study of PEM 29–31 …”