Collaborative Research: An Integrated Experimental/Computational Study of the Mechanics of Nanofiber Networks

该奖项支持为凝胶、橡胶、组织支架、纤维素产品和非织造布等纳米纤维材料表征聚合物纳米纤维网络的有效机械强度和延展性的研究。尽管人们对宏观尺度的纤维网络有很好的理解，但纳米纤维的行为与宏观尺度的纤维不同，这是因为纳米纤维具有微尺度纤维所没有的卓越的延展性和强度，以及纳米纤维之间相对较强的粘附性。这两个显著的特点为控制和极大地提高聚合物纳米纤维网络的有效机械强度和延展性带来了目前尚未探索的机会。由聚合物或生物材料组成的有序和随机的纳米纤维网络在生物组织、组织支架、生物医学植入物、静电纺丝空气过滤系统、纤维素产品等中无处不在。本科生研究人员将与教师和研究生合作开发基于网络的互动教学课堂模块，向学生介绍纤维网络的概念和设计。研究重点是规则和随机的准2D纳米纤维网络，以及聚合物纳米纤维之间结合和非结合(粘合)的相互作用，以确定构建具有特殊强度和韧性的网络的方法。为此，将遵循一个紧密集成的实验/计算研究计划，其中将使用新的实验来确定聚苯乙烯(PS)和聚丙烯腈(PAN)纳米纤维(直径100-500 nm)的力学响应，以及粘合纤维相互作用和粘合PS-PS和PAN-PAN纤维接触的强度。这些数据将被用来校准网络力学的计算模型，该模型将考虑纳米纤维的粘合、粘合和拓扑相互作用，并将用于确定这些相互作用在具有不同网络体系结构和参数集的网络的整体力学行为中的相对重要性。该模型将基于在规则和随机光纤网络上进行的有针对性的实验来验证，并将用于执行网络结构的优化，以增强强度和韧性。

This award supports research to characterize the effective mechanical strength and ductility of polymer nanofiber networks for nanofilamentous materials such as gels, rubber, tissue scaffolds, cellulose products and non-wovens. Although macroscale fiber networks are quite well understood, nanofibers behave differently from their macroscale counterparts due to the coupled effect of their outstanding ductility and strength that are not observed in microscale fibers, and the relatively strong adhesion between nanofibers. These two distinguishing features lead to currently unexplored opportunities for controlling and vastly improving the effective mechanical strength and ductility of polymer nanofiber networks. Ordered and random networks of nanofilaments composed of polymeric or biological materials are omnipresent in biological tissues, tissue scaffolds, biomedical implants, electrospun air filtration systems, cellulose products, etc. Undergraduate researchers will work with the faculty and graduate students to develop web-based, interactive educational classroom modules to introduce students to the concepts of fiber networks and design.The research focuses on regular and random quasi-2D nanofiber networks with bonded and non-bonded (cohesive) interactions between polymeric nanofibers, to identify ways for constructing networks with exceptional strength and toughness. To this effect, a tightly integrated experimental/computational research program will be followed in which the mechanical response of polystyrene (PS) and polyacrylonitrile (PAN) nanofibers (100-500 nm diameter), and the strength of bonded fiber interactions and adhesive PS-PS and PAN-PAN fiber contacts will be determined using novel experiments. The data will be employed to calibrate a computational model for the network mechanics, which will account for bonded, adhesive and topological interactions of nanofibers and will be used to determine the relative importance of these interactions in the overall mechanical behavior of networks with various network architectures and parameter sets. The model will be validated based on targeted experiments performed on regular and random fiber networks, and will be applied to perform optimization of the network structure for enhanced strength and toughness.