Overcoming Challenges in Processing Biobased Materials for Soft Robotics

Electronic materials and robotic devices are pervasive throughout modern society and with increasing demand comes a growing interest in improving the sustainability of these products. One of the most promising methods to improve sustainability is to replace key components with biobased materials, which are derived from renewable biomass sources. However, these materials are often very challenging to process due to a large degree of heterogeneity, impurities from the feedstock, batch-to-batch variation, and abundance of functional groups with strong molecular interactions. This becomes even more important for applications such as soft robotics where small changes in microstructure can lead to large changes in performance. Applying systematic study of the formulation and the processing conditions in tandem, we can provide insights into how to overcome these unique challenges in biobased materials, working with materials from cellulose nanocrystals to sodium alginate to silk fibroin. Strong hydrogen bonding and the presence of charged functional groups leads to changes in rheology that require adjustments in processing parameters, while impurities from the biomass source lead to inconsistency in the materials and development of additional purification schemes to reduce variability in the output product and improve quality. Underlying the design of these soft materials from biobased sources is a strong link between the formulation and the process and only with this vision towards manufacturability can we realistically improve the sustainability of these complex products.