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

微纤维纤维素(MFC)是造纸过程中产生的一种废品。它被用于商业加工，用于某些工业用途，但它也作为一种潜在的流变性改进剂应用于消费、织物和家居护理产品。流变剂是添加到某些产品中以定制其流动行为的材料。MFC是非离子的，这使得它与广泛的产品配方兼容，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是以高度缠绕的纤维在水中的浓缩浆形式提供的，这些纤维很难在大多数产品中分散。这个由利哈伊大学和宝洁公司合作的GOALI项目将研究MFC的结构如何依赖于参数，如温度、宿主溶液的组成和流动对MFC施加的力。使用几种探测MFC纤维微结构排列的技术，研究人员探索了微结构中的转变，这些转变可以促进MFC在有用产品中的分散。将造纸业的MFC废物重新用作消费品的添加剂将减少MFC处理的需要，并降低有价值的消费品的制造成本。研究团队将从事各种外展活动，包括达芬奇科学中心的项目，教育公众胶体和流变学，指导对STEM领域感兴趣的初中生和高中生，以及培训本科生和研究生进行研究。这个目标项目的总体目标是表征MFC支架的时空流变演变，使其能够用作消费者、织物和家居护理产品的流变调节剂。MFC的纤维尺寸与目前使用的流变性改进剂的纤维尺寸相当，但与其他改性剂不同的是，MFC对胶体的电荷可以忽略不计。通过使用微观流变学和显微镜表征MFC的微观结构演变，通过表征MFC体系的体流变学的演变，以及通过使用独特的微流体平台和多粒子跟踪微观流变学来确定相变后的平衡性质和支架结构，将探索MFC的潜在优势。由于三种驱动力：温度、周围溶液的变化和流动诱导的机械力，MFC溶液将在相变期间进行表征。这些知识将使这些材料能够用作配方产品行业的流变性改进剂。研究结果将确定导致均一MFC悬浮的材料，并确定导致稳定悬浮的微观结构和宏观结构和性能。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.