Rahman Muhammad M, Netravali Anil N
Department of Fiber Science & Apparel Design, Cornell University, 37 Forest Home Drive, Ithaca, New York 14853, United States.
ACS Macro Lett. 2016 Sep 20;5(9):1070-1074. doi: 10.1021/acsmacrolett.6b00621. Epub 2016 Sep 9.
Conventional bacterial cellulose (BC) membranes are formed by randomly aligned nanofibrils stacked in a reticulated fashion. While such membranes are used in many applications, full utilization of the mechanical properties of nanofibrils has not been achieved in composite materials because of their random alignment. In the present research, aligned BC, in the form of arrays, has been developed through an optimally designed polydimethylsiloxane grating substrate placed at the air-liquid interface of the culture medium. The substrate prepared with the help of a 3-D printed mold served as an alignment template providing bacteria a preferred direction for BC growth. Additional alignment in BC arrays was obtained by stretching the hydrogel at a controlled strain rate and strain ratio. The degree of orientation, Young's modulus, and tensile strength of aligned BC arrays increased by approximately 184, 409, and 256%, respectively, compared to the conventional BC pellicle. Such aligned BC arrays could open up future opportunities to design lightweight advanced "green" composites as alternatives to petroleum-based composites for a range of technical applications.
传统的细菌纤维素（BC）膜是由随机排列的纳米纤维以网状方式堆叠而成。虽然这种膜在许多应用中都有使用，但由于纳米纤维的随机排列，复合材料尚未充分利用其机械性能。在本研究中，通过放置在培养基气液界面的优化设计的聚二甲基硅氧烷光栅基板，开发出了呈阵列形式的排列BC。借助3D打印模具制备的基板作为排列模板，为细菌提供了BC生长的优选方向。通过以受控的应变速率和应变比拉伸水凝胶，在BC阵列中获得了额外的排列。与传统的BC薄膜相比，排列BC阵列的取向度、杨氏模量和拉伸强度分别提高了约184%、409%和256%。这种排列BC阵列可为设计轻质先进的“绿色”复合材料开辟未来机遇，作为一系列技术应用中石油基复合材料的替代品。
