Foldable Conductive Cellulose Fiber Networks Modified by Graphene Nanoplatelet-Bio-Based Composites
Foldable Conductive Cellulose Fiber Networks Modified by Graphene Nanoplatelet-Bio-Based Composites
复制标题
DOI：
10.1002/aelm.201500224
复制
发表时间：
2015-12-01
影响因子：
6.2
通讯作者：
Cingolani, Roberto
中科院分区：
文献类型：
--
作者：
Cataldi, Pietro;Bayer, Ilker S.;Cingolani, Roberto
真正的可折叠柔性电子部件需要用导电材料改性的可折叠基板，该导电材料即使在硬机械操作和多次折叠事件之后也可以保持其导电性和机械完整性。在这里，设计并制造了利用全生物降解组分（基底和聚合物基质）和石墨烯纳米片的组合的这种材料。将市售的热塑性淀粉基聚合物（Mater-Bi）和石墨烯纳米片同时分散在有机溶剂中以配制导电油墨。油墨喷涂在纯纤维素片材上，干燥后热压成纤维网。所得的纳米结构柔性复合材料显示出优异的各向同性导电性，根据生物聚合物和石墨烯纳米片之间的相对浓度，达到接近10 Ω sq（-1）的非常低的薄层电阻值。透射电子显微镜结果表明，在热压过程中，石墨烯纳米片物理嵌入到纤维素纤维中，导致柔性复合材料的高电导率。纸状柔性导体可以承受许多严重的折叠事件，保持其机械和电气性能，并且相对于未折叠的对应物仅显示出其电导率的轻微降低。与导电纸技术不同，所提出的纸状柔性导体由于压力诱导浸渍而表现出两侧各向同性导电性。
Truly foldable flexible electronic components require a foldable substrate modified with a conducting material that can retain its electrical conductivity and mechanical integrity even after hard mechanical manipulations and multiple folding events. Here, such a material exploiting the combination of all-biodegradable components (substrate and the polymer matrix) and graphene nanoplatelets is designed and fabricated. A commercially available thermoplastic starch-based polymer (Mater-Bi) and graphene nanoplatelets are simultaneously dispersed in an organic solvent to formulate conductive inks. The inks are spray painted on pure cellulose sheets and hot-pressed into their fiber network after drying. The resultant nanostructured flexible composites display excellent isotropic electrical conductivity, reaching very low sheet resistance value approximate to 10 Omega sq(-1), depending on the relative concentration between the biopolymer and the graphene nanoplatelets. Transmission electron microscopy results indicated that during hot-pressing, graphene nanoplatelets are physically embedded into the cellulose fibers, resulting in high electrical conductivity of the flexible composite. The paper-like flexible conductors can withstand many severe folding events, maintaining their mechanical and electrical properties and showing only a slight decrease of their electrical conductivity with respect to the unfolded counterparts. Unlike conductive paper technologies, the proposed paper-like flexible conductors demonstrate both sides isotropic conductivity due to pressure-induced impregnation.