Hydrogels are a widely used ionic conductor in on-skin electronic and iontronic devices. However, hydrogels dehydrate in the open air and freeze at low temperatures, limiting their real applications when they are attached on skin or exposed to low temperatures. Polymer-ionic liquid gels can overcome these two obstacles, but synthetic ionic liquids are expensive and toxic. In this work, we present an ionic conductor based on polyacrylic acid (PAAc) and deep eutectic solvents (DESs) that well addresses the aforementioned challenges. We polymerize acrylic acid in DESs to get the PAAc–DES gel, which exhibits excellent stretchability (> 1000%), high electrical conductivity (1.26 mS cm⁻¹), high adhesion to the skin (~ 100 N m⁻¹), as well as good anti-drying and anti-freezing properties. We also demonstrate that the PAAc-DES gel can be used as an on-skin electrode to record the surface electromyographic signal with high signal quality, or as a transparent stretchable electrode in iontronic devices that can work at –20 °C. We believe that the PAAc–DES gels are an ideal candidate as epidermal electrodes or transparent stretchable electrodes.

水凝胶是皮肤电子和离子电子设备中广泛使用的离子导体。然而，水凝胶在露天脱水并在低温下冻结，当它们附着在皮肤上或暴露在低温下时，限制了它们的实际应用。聚合物-离子液体凝胶可以克服这两个障碍，但合成离子液体价格昂贵且有毒。在这项工作中，我们提出了一种基于聚丙烯酸 (PAAc) 和深共熔溶剂 (DESs) 的离子导体，可以很好地解决上述挑战。我们在 DESs 中聚合丙烯酸以获得 PAAc-DES 凝胶，该凝胶具有出色的拉伸性 (> 1000%)、高导电性 (1.26 mS cm ^-1 )、对皮肤的高粘附性 (~ 100 N m ^-1)，以及良好的防干燥和防冻性能。我们还证明了 PAAc-DES 凝胶可用作皮肤电极，以高信号质量记录表面肌电信号，或用作可在 –20 °C 下工作的离子电子设备中的透明可拉伸电极。我们相信 PAAc-DES 凝胶是作为表皮电极或透明可拉伸电极的理想选择。