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

该奖项支持研究表征纳米丝状材料（如凝胶、橡胶、组织支架、纤维素产品和无纺布）的聚合物纳米纤维网络的有效机械强度和延展性。虽然宏观尺度的纤维网络已经被很好地理解，但纳米纤维的表现与宏观尺度的纤维不同，这是由于它们在微观尺度纤维中没有观察到的突出的延展性和强度的耦合效应，以及纳米纤维之间相对较强的粘附性。这两个显著的特征为控制和大大提高聚合物纳米纤维网络的有效机械强度和延展性提供了目前尚未开发的机会。由聚合物或生物材料组成的有序和随机的纳米丝网络在生物组织、组织支架、生物医学植入物、静电纺空气过滤系统、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交互式教育课堂模块，向学生介绍光纤网络和设计的概念。研究重点是聚合物纳米纤维之间具有键合和非键合（内聚）相互作用的规则和随机准二维纳米纤维网络，以确定构建具有特殊强度和韧性的网络的方法。为此，一个紧密结合的实验/计算研究计划将遵循，其中聚苯乙烯（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的强度和粘合剂PS-PS和PAN-PAN纤维接触将通过新的实验来确定。这些数据将用于校准网络力学的计算模型，该模型将考虑纳米纤维的粘合、粘附和拓扑相互作用，并将用于确定这些相互作用在具有各种网络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进行验证，并将用于优化网络结构以增强强度和韧性。

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.