Recent advances in polymer synthesis have allowed remarkable control over chain microstructure and conformation. Capitalizing on such developments, here we create well-controlled chain folding in sulfonated polyethylene, leading to highly uniform hydrated acid layers of subnanometre thickness with high proton conductivity. The linear polyethylene contains sulfonic acid groups pendant to precisely every twenty-first carbon atom that induce tight chain folds to form the hydrated layers, while the methylene segments crystallize. The proton conductivity is on par with Nafion 117, the benchmark for fuel cell membranes. We demonstrate that well-controlled hairpin chain folding can be utilized for proton conductivity within a crystalline polymer structure, and we project that this structure could be adapted for ion transport. This layered polyethylene-based structure is an innovative and versatile design paradigm for functional polymer membranes, opening doors to efficient and selective transport of other ions and small molecules on appropriate selection of functional groups.

聚合物合成的最新进展已实现了对链微结构和构象的显着控制。利用这种发展，我们在磺化聚乙烯中创造了可控的链折叠，从而产生了亚纳米厚度的高度均匀的水合酸性层，并具有高质子传导性。线性聚乙烯包含精确悬挂在每二十一个碳原子上的磺酸基，这些碳原子引起紧密链折叠形成水合层，而亚甲基链段则结晶。质子传导率与Nafion 117（燃料电池膜的基准）相当。我们证明了良好控制的发夹链折叠可用于结晶聚合物结构内的质子传导性，并且我们预计该结构可适于离子传输。