GOALI: Determination of the Structure and Properties of Microfibrillated Cellulose during Dynamic Phase Transitions

微纤化纤维素（MFC）是造纸过程中产生的废物。它被商业加工用于一些工业用途，但它也有潜在的应用，作为流变改性剂在消费品，织物和家庭护理产品。流变改性剂是添加到某些产品中以定制其流动特性的材料。MFC是非离子型的，这使得它与各种产品配方兼容，但它必须分散在整个产品中以改变产品的性能。挑战在于MFC是作为高度纠缠的纤维在水中的浓缩浆料提供的，在大多数产品中很难分散。这个GOALI项目是里海大学和宝洁公司的合作项目，将研究MFC的结构如何取决于温度、主溶液的组成以及由于流动而施加在MFC上的力等参数。研究人员利用几种技术来探测MFC纤维的微观结构安排，探索微观结构中的转变，这些转变可以增强MFC在有用产品中的分散。将造纸工业的MFC废物作为消费品的添加剂重新利用，将减少对MFC的处置需求，并降低有价值消费品的制造成本。研究团队将参与各种外展活动，包括在达芬奇科学中心向公众宣传胶体和流变学，指导对STEM领域感兴趣的中学生和高中生，以及培训本科生和研究生进行研究。这个GOALI项目的总体目标是表征MFC支架的空间和时间流变演变，使其能够作为消费者、织物和家庭护理产品的流变改性剂使用。MFC的纤维尺寸与目前使用的流变改性剂的纤维尺寸相当，但与其他改性剂不同的是，MFC对胶体的电荷可以忽略不计。通过使用微流变学和显微镜表征MFC的微观结构演变，通过表征MFC系统的体流变学演变，通过使用独特的微流控平台和多粒子跟踪微流变学确定相变后的平衡特性和支架结构，探索MFC的潜在优势。由于温度、周围溶液的变化和流动引起的机械力这三个驱动力，MFC溶液将在相变过程中进行表征。这些知识将使这些材料成为配方产品工业的流变改性剂。研究结果将确定导致均匀MFC悬浮液的材料，并确定导致稳定悬浮液的微观结构和宏观结构和性能。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Microfibrillated cellulose (MFC) is a waste product generated during paper manufacturing. It is processed commercially for some industrial uses, but it also has a potential application as a rheological modifier in consumer, fabric and home care products. Rheological modifiers are materials added to certain products to customize their flow behavior. MFC is non-ionic, which makes it compatible with a wide range of product recipes, but it must be dispersed throughout a product to modify the product's properties. The challenge is that MFC is supplied as a concentrated slurry of highly entangled fibers in water that are difficult to disperse in most products. This GOALI project, which is a collaboration between Lehigh University and Procter and Gamble, will investigate how the structure of MFC depends on parameters such as the temperature, composition of the host solution and forces exerted on MFC due to flow. Using several techniques that probe the microstructural arrangements of the MFC fibers, the researchers explore transitions in the microstructure that can enhance dispersal of MFC in useful products. Repurposing MFC waste from the paper industry as additives for consumer products will reduce the need for MFC disposal and reduce manufacturing costs of valuable consumer products. The research team will engage in a variety of outreach activities, including programs at the Da Vinci Science Center to educate the public in colloids and rheology, mentoring middle school and high school students interested in STEM fields, and training undergraduate and graduate students in research.The overall goal of this GOALI project is to characterize the spatial and temporal rheological evolution of an MFC scaffold to enable its use as a rheological modifier for consumer, fabric and home care products. MFC has a fiber size that is comparable to the fiber size of rheological modifiers in current use, but unlike other modifiers, MFC has negligible charge on the colloid. The potential advantages of MFC will be explored by characterizing the microstructural evolution of MFC using microrheology and microscopy, by characterizing the evolution of bulk rheology of MFC systems, and by determining equilibrium properties and scaffold structure after phase transitions using a unique microfluidic platform and multiple particle tracking microrheology. MFC solutions will be characterized during phase transitions due to three driving forces: temperature, changes in the surrounding solution and flow-induced mechanical forces. This knowledge will enable the use of these materials as rheological modifiers for the formulated product industry. The results of the research will identify materials that lead to homogeneous MFC suspensions and determine the microstructure and macroscopic structure and properties that lead to stable suspensions.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.