Tuning the ion channel network of perfluorosulfonated membranes via a facile sacrificial porogen approach

Direct Measurements of Electroviscous Phenomena in Nafion Membranes

“…From Table 1 it is seen that κ H for all membranes are in the range from about 1.5 to 4.5 ×10 −17 m 2 Pa −1 s −1 where the lowest value is observed for an NC membrane cast from a Nafion solution while the highest value is seen for the N-SPS30 membrane. This is expected since the N-SPS30 contains an additive (porogen) that increases the characteristic dimension of the ion-channels, thereby increasing the permeability [22]. Additionally, it is seen that the relative electroviscous effect, stated as the ratio κ H κ −1 H , does not change significantly among the different membranes.…”

“…Nafion117 (dry thickness: 178 µm), Nafion212 (dry thickness: 50 µm), and Nafion solution (ion exchange capacity (iec) = 0.95 to 1.01 meq g −1 ) were acquired from Fuel Cell Store (https://www.fuelcellstore.com/). The cast membranes were synthetized by following the approach described by Kristensen et al [22]. Briefly: 2 g of Nafion were dissolved in 30 mL Dimethylacetamide (DMAc, anhydrous 98.9 %, Sigma Aldrich) and sulfonated polystyrene (SPS, 30% w/v aqueous solution, MW 75,000, iec SPS = 5.4 meq g −1 , Alfa Aesar) was added.…”

“…Afterward, the membranes were dried under vacuum at 25 • C and then rinsed in milli-Q water. The extruded and cast membranes were chemically pretreated prior to use as in Reference [22]: the membranes were pretreated by boiling in H 2 O 2 (3 wt%), then H 2 SO 4 (1 M), and finally in Milli-Q water. The membranes were stored in 1 M LiCl until use (at least 24 h) to obtain the Li + form.…”

Флуоресценция N,n'-Бис(салицилиден)-1,3-Пропилендиамина И Его Галогенпроизводных В Перфторсульфоновой Мембране

“…отражают серьезные стерические затруднения диффузии и размещения крупных молекул в узких полостях носителя. Тем не менее результаты сорбции можно считать вполне значимыми, поскольку (в допущении ее отсутствия) простая пропитка мембран (объем порового пространства ∼ 0.2 сm 3 • g −1 [4-6]) используемыми 10 −4 mol • l −1 растворами оснований обеспечила бы их содержание лишь на уровне 10 −8 mol • g −1 . Проявление азометинов как тетрадентантных оснований состоит в их способности допировать электронную плотность.…”

“…обрамленных" связанными сульфогруппами [1][2][3]. Благодаря высокой протонной проводимости мембраны до настоящего времени исследуются и применяются в качестве твердых электролитов в низкотемпературных топливных элементах.…”