Hierarchical biopolymer‐based materials and composites

Abstract

The mass production and disposal of non‐degradable fossil‐based plastics is responsible for alarming environmental and social issues when not managed responsibly. Towards manufacturing environmentally‐friendly materials, biopolymers, that is, polymers synthesized by living organisms, emerge as promising sustainable alternatives as they combine attractive mechanical properties, compostability, and renewable sourcing. In this review, we analyze the structural and mechanical properties of three of the most studied biopolymer classes: cellulose, chitin, and protein beta‐sheet structures. We first discuss the hierarchical structure of the biopolymers and how their rich interaction networks induce appealing mechanical properties. Then, we review different fabrication and processing methods to translate these attractive properties into macroscopic materials and composites. Finally, we discuss a nascent approach, which leverages the direct use of microorganisms, in the form of intact cells, tissues or dissociated biological matter (biomatter), as meso‐scale material building blocks. These non‐ or little pre‐processed biomatter building blocks are composed of the biopolymer structural elements (molecular‐nano scale), but also inherit the higher‐scale hierarchical characteristics. Processing‐structure–property relationships for biomatter‐based materials are discussed, emphasizing on the role of hierarchical arrangement, processing‐induced transformations, and intermolecular bonding, on the macroscopic mechanical properties. Finally, we present a perspective on the role of biopolymers in a circular economy.

Measuring mechanical cues for modeling the stromal matrix in 3D cell cultures

“…74 Furthermore, our microrheometer data indicate a drop in the microscale stiffness for hydrogels at a 30 mM concentration of the Ca 2+ crosslinker. We hypothesize the stiffness reduction at the measured locations to be related to the crosslinker oversaturation, 67 plausibly resulting in Ca 2+ precipitates 75 which disturb the fibrillar distribution within the network, specifically, alignment and connectivity.…”

“…66 This likely originates from the intrinsic material hierarchy, typical for biopolymer networks. 67,68 While bulk rheometry reports the macroscopical response of the complex material, the network heterogeneities, which are experienced by cells, remain undetected. In contrast, when biomaterials are probed locally, within a small distinct volume as in magnetic microrheology, the response of the surrounding network correlates with the response of the stromal tissue when cells exert forces on its microenvironment.…”

Advances, Synergy, and Perspectives of Machine Learning and Biobased Polymers for Energy, Fuels, and Biochemicals for a Sustainable Future

“…In energy conversion systems, the contribution of ML to the progress of biobased polymers is crucial . The role of biobased polymers in fuel cells and other energy conversion devices is optimized by employing ML for the precise tailoring of material properties. , The potential of ML in guiding the development of high-performance, sustainable biobased polymer components for energy conversion is significant. It ensures the efficiency and sustainability of these systems, thus playing a crucial role in enhancing overall energy conversion processes and technologies …”

Fabricating Strong and Stiff Bioplastics from Whole Spirulina Cells

“…[20] The applications of TPS are limited by its relatively low strength of less than 6 MPa. [18,19] Lignocellulosic polymers can provide a biobased source for materials with higher strength and stiffness values due to the inherent high degree of crystallinity and strength of cellulose, [1,18,[21][22][23][24] and can be considered carbon sinks when made from waste biomass that would otherwise be incinerated. Still, the extraction of cellulose from biomass involves multi-step processes and harsh chemicals.…”

“…[28] In an effort to circumvent extraction processes, biobased and compostable materials produced from whole plant, bacterial, fungal, or algal biomass, without extracting components, have been reported. [1,24,[29][30][31][32][33][34][35][36] Among the studied organisms, algal species can be considered as a potentially disruptive material platform as they grow rapidly in a wide variety of natural aquatic environments as well as in cultures. [28,30] This versatility may allow for algae to be grown in close proximity to facilities where they are transformed into bioplastic materials, reducing transportation emissions and costs.…”