A. R. Smith Department of Chemistry, Appalachian State University, 525 Rivers Street, Boone, NC 28608, USA.
Soft Matter. 2017 Sep 27;13(37):6542-6554. doi: 10.1039/c7sm01169e.
2,2'-Bipyridine-terminated poly(dimethylsiloxane)s (bpyPDMS) with number average molecular weights, M, of 3300, 6100, 26 200, and 50 000 g mol were synthesized. When mixed with Fe(BF) at low concentrations, red solutions formed with UV-vis spectra that match those of iron(ii) tris(2,2'-bipyridine) (Fe(bpy)). Upon solvent evaporation, Fe(bpy) crosslinked PDMS networks (bpyPDMS/Fe(ii)) formed, and were studied using oscillating shear rheometry. The shear storage moduli (0.084 to 2.6 MPa) were found to be inversely proportional to the M of the PDMS, though the storage moduli at low molecular weights greatly exceeded the storage moduli of comparable covalently crosslinked PDMS networks. The shear storage moduli exhibited the characteristic rubbery plateau up to ∼135 °C. Films of bpyPDMS/Fe(ii) coated onto electrodes were found to be electrochemically active, especially so when the PDMS M is low. The Fe(bpy) crosslinks can be reversibly oxidized over ∼500 nm away from the electrode surface in the presence of a suitable electrolyte.
2,2'-联吡啶封端的聚二甲基硅氧烷（bpyPDMS），数均分子量 M 分别为 3300、6100、26200 和 50000 g/mol，被成功合成。当与低浓度的 Fe(BF)混合时，会形成红色溶液，其紫外可见光谱与铁(ii)三（2,2'-联吡啶）（Fe(bpy)）相匹配。溶剂蒸发后，Fe(bpy)交联的 PDMS 网络（bpyPDMS/Fe(ii)）形成，并通过振荡剪切流变仪进行了研究。剪切储能模量（0.084 至 2.6 MPa）与 PDMS 的 M 成反比，尽管低分子量的储能模量大大超过了可比的共价交联 PDMS 网络的储能模量。剪切储能模量在约 135°C 时表现出典型的橡胶平台特性。涂覆在电极上的 bpyPDMS/Fe(ii)薄膜被发现具有电化学活性，尤其是当 PDMS 的 M 较低时。在合适的电解质存在下，Fe(bpy)交联可以在距电极表面约 500nm 处可逆地氧化。
