Manufacture Biomimetic Spatially Varying Fiber Arrangement in Soft Fiber Reinforce Composites Using Aerodynamic Fiber Deposition

Biological tissues, such as skin, muscle, cartilage, and bone are composed of nano/microfibers embedded in a matrix. The fiber arrangement varies over complex tissue geometries to efficiently bear load and regulate deformation. Reproducing such fiber arrangements can lead to more robust and biocompatible medical implants and advanced biomimetic robots that are as adaptive and agile as animals. However, given the small fiber diameter, it can take more than 100km nano/microfibers to fill up a 1ml volume. No existing technology can handle such fiber lengths while controlling spatially varying fiber arrangement. This award supports the investigation of a new technology, aerodynamic fiber deposition, to address this challenge. Aerodynamic fiber deposition uses airflow to focus fibers into a small deposition spot and control the fiber arrangement within the spot. Spatially varying fiber arrangement is achieved by changing fiber arrangement as the deposition spot moves. High throughput is achieved as airflow can manipulate thousands of fibers simultaneously. The research can lead to biomimetic materials that rival the performance of biological tissues, thus enabling its utility in a wide range of medical and robotic devices. The project will also support the participation of underrepresented groups in research and develop related workshops for early science and engineering education. The project will address a fundamental challenge in nano/microfiber manufacturing. 3D printing techniques such as direct ink writing can precisely control fiber arrangements but cannot handle long fiber lengths and throughput remains low. Fiber spinning technologies such as electrospinning and centrifugal spinning can manufacture nano/microfibers with a high throughput but have limited control over the fiber arrangement. Aerodynamic fiber deposition combines the high throughput of established nano/microfiber spinning technologies and a spot-wise deposition like 3D printing to control the spatially varying nano/microfiber arrangements. This research will integrate an electric field and an air jet to achieve a deposition spot smaller than 1cm and will characterize how the deposition spot size affects the resolvable spatial variation in fiber arrangements. The fibers will be embedded into an elastomeric matrix to study how the spatially varying fiber arrangement affects the inhomogeneous mechanical properties. This research will lay the foundation for designing biomimetic fiber-reinforced soft materials using aerodynamic fiber deposition and adapting the technology to applications that require different throughput and resolution. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.