CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
J Phys Chem B. 2010 Oct 21;114(41):13121-7. doi: 10.1021/jp104514t.
For development of proton conductive membranes, it is a difficult dilemma to balance proton conductivity and methanol permeability; however, this research proposes a simple strategy to solve this problem, i.e., embedding a proton conductive "barrier" into the perflorosulfonated matrix. The strategy is exemplified by embedding the amphoteric sulfonated poly(phthalazinone ether sulfone kentone) (SPPESK) into a semicrystalline perflorosulfonic acid polymer matrix (FSP). After being annealed, the domain of SPPESK is converted to the barrier. Two acid-base interactions constitute the barrier for both the transfer of protons and the blockage of methanol, respectively. On one hand, poorly hydrophilic ionic acid-base interactions (-SO(3)(-)...NH(+)-) are formed between sulfonic acid group and phthalazinone group through annealing and are useful for methanol blocking. On the other hand, more hydrophilic hydrogen-bonded acid-base interaction (-SO(3)H...(H(2)O)(n)...N-, n ≤ 3) can also be formed under hydrated condition and facilitate proton transport according to the Grotthuss-type mechanism. As a result, the final membrane exhibits an extremely low methanol permeability (30% of that of Nafion-112) and an excellent fuel cell performance (as compared with Nafion-112 at 80 °C).
对于质子传导膜的发展，平衡质子传导率和甲醇渗透率是一个困难的两难境地；然而，本研究提出了一个简单的策略来解决这个问题，即在全氟磺酸基体中嵌入质子传导“障碍”。该策略的一个例子是将两性磺化聚（苯并二恶唑酮醚砜酮）（SPPESK）嵌入半结晶全氟磺酸聚合物基体（FSP）中。退火后，SPPESK 域转化为障碍。两种酸碱相互作用分别构成质子传递和甲醇阻断的障碍。一方面，通过退火在磺酸基团和苯并二恶唑酮基团之间形成了较差亲水性的离子酸碱相互作用（-SO3(-)…NH(+)），有利于甲醇阻断。另一方面，在水合条件下也可以形成更亲水性的氢键酸碱相互作用（-SO3H…（H2O）（n）…N-，n≤3），根据质子转移的 Grotthuss 型机制有利于质子传输。结果，最终的膜表现出极低的甲醇渗透率（比 Nafion-112 低 30%）和优异的燃料电池性能（在 80°C 时与 Nafion-112 相比）。
