Ali Reza Nazmi

Microorganisms metabolising low-value carbon sources can produce a diverse range of bio-based and biodegradable materials compatible with circular economy principles. One such material is bacterial cellulose (BC), which can be obtained in high purity through the fermentation of sweetened tea by a Symbiotic Culture of Bacteria and Yeast (SCOBY). In recent years, there has been a growing research interest in SCOBYs as a promising solution for sustainable material design. In this work, we have explored a novel method to grow SCOBYs vertically using a waste-based scaffold system. Waste sheep wool and cotton fabric were soaked in a SCOBY infusion to serve as scaffolds, carrying the infusion and facilitating vertical growth through capillary forces. Remarkably, vertical membrane growth up to 5 cm above the liquid–air interface (LAI) was observed after just one week. Membranes with different microstructures were found in sheep wool and cotton, randomly oriented between the scaffold fibre, resulting in a high surface area. This study demonstrated that vertical growth in scaffolds is possible, proving the concept of a new method of growing composite materials with potential high-value applications in biomedicine, energy storage, or filtration.

This study investigates the 3D extrusion printing of a carboxymethyl cellulose (CMC)–gelatin complex coacervate system. Various CMC–gelatin coacervate hydrogels were prepared and analyzed to achieve this goal. The impact of the CMC–gelatin ratio, pH, and total biopolymer concentration on coacervation formation and rheological properties was evaluated to characterize the printability of the samples. Turbidity results indicated that the molecular interactions between gelatin and CMC biopolymers are significantly pH-dependent, occurring within the range of pH 3.7 to pH 5.6 for the tested compositions. Confocal Laser Scanning Microscopy (CLSM) confirmed the presence of coacervates as spherical particles within the optimal coacervation range. Scanning electron microscopy micrographs supported the CLSM findings, revealing greater porosity within this optimal pH range. Rheological characterization demonstrated that all CMC–gelatin hydrogels exhibited pseudoplastic behavior, with an inverse correlation between increased coacervation and decreased shear viscosity. Additionally, the coacervates displayed lower tackiness compared to gelatin hydrogels, with the maximum tackiness normal force for various CMC–gelatin ratios ranging from 1 to 15 N, notably lower than the 29 N observed for gelatin hydrogels. Mixtures with CMC–gelatin ratios of 1:15 and 1:20 exhibited the best shear recovery behavior, maintaining higher strength after shear load. The maximum strength of the CMC–gelatin coacervate system was found at a biopolymer concentration of 6%. However, lower biopolymer content allowed for consistent extrusion. Importantly, all tested samples were successfully extruded at 22 ± 2 °C, with the 1:15 biopolymer ratio yielding the most consistent printed quality. Our research highlights the promise of the CMC–gelatin coacervate system for 3D printing applications, particularly in areas that demand precise material deposition and adjustable properties.

Biobased composites are ideally poised to replace fossil-based raw materials currently used in mass production. However, recent production figures indicate that the volume of biobased polymers is still below 1% of total plastic production. This underperformance is attributed to the poor demand and acceptance of biocomposites caused by technical and perceptual challenges. Most of the research focused on biocomposites has been aimed at addressing technical challenges, but to solve the unexplored perceptual issues, we propose a novel design process for creating new biocomposites by programming the perceptual characteristics of biocomposites. By understanding the role of material characteristics (colour, patterns, texture, roughness) in forming these attributes, we propose that novel biocomposites could be created to suit specific consumer needs. A prediction model for generating desired material perception has been suggested based on the material-attribute correlations. This model could assist in developing novel sustainable materials which are perceptually appealing to consumers, and a modified design process based on consumer perception has been proposed in this paper. This new process can help material engineers and product designers create new biocomposites that align with the emotional demands of the product segment and user experience.

The product designer’s role in promoting sustainable materials is crucial, as designers make material selections for products on behalf of consumers. This role is even more critical in the case of sustainable materials like biobased composites, as a legacy of poor perception of aesthetics and value handicaps these materials. In this study, we examine this assertion of designers’ ability to empathise with consumers and investigate if their perception of biobased composites aligns with that of consumers. A perception framework for biobased composites proposed in prior research is applied to predict consumer perception of materials in this study. The roles of various visual/tactile factors that affect crucial perceptual attributes (beauty, naturality, strength and value) are also examined. An evident perceptual incongruity between designers and consumers was observed, diminishing the claim of designers’ ability to empathise with consumers in the remit of biobased composites. It is also seen that the proposed perception framework generates reliable predictions of consumer perception for biobased composites and can thus assist designers in material selection. This approach can help designers select materials that better align with consumer expectations, furthering the use of sustainable materials in product design.

Amidst population growth and challenges with existing fertilizers, the development of smart and environmentally friendly agrochemicals is imperative. While 3D printing is widespread, its potential in slow-release agrochemicals remains unexplored. This proof-of-concept study employed solvent casting and 3D printing to develop agar–urea structures. These structures, comprising 2.5% (w/w) agar, incorporated either 7% (w/w) or 13% (w/w) urea as nitrogen nutrients. Rheological, mechanical, and morphological properties and sorption capabilities were explored. Rheological analysis revealed a substantial impact of urea, enhancing material resistance to deformation. In mechanical tests, inclusion of urea showed no significant impact on compressive strength. SEM analysis confirmed the successful entrapment of urea within the agar matrix. The inclusion of urea resulted in a diminished water sorption capacity, attributed to the urea–water interactions disrupting the hydrogen bonding ability of agar. Agar–urea inks were employed in 3D printing utilizing the direct-ink writing technique, and the nitrogen release behavior was investigated. Results revealed nearly complete urea release in the positive control within 48 h. In contrast, agar–urea formulations with 7% (w/w) and 13% (w/w) achieved nitrogen release rates of 88.8% and 94.4%, respectively, suggesting potential for 3D-printed agar formulations to modify the immediate release behavior seen in conventional urea fertilizers.

The role of material perception is vital in designing new materials and products which are widely accepted by consumers. This is of even greater significance in the case of sustainable materials like biobased composites, which are not familiar to the average consumer. Understanding the effect of visual and tactile characteristics of the biobased composites on the formation of material perception could help material engineers and designers to create sustainable and high-value materials. In this study of biobased composites, the semantic differential method is used to assess material attributes (in digital and physical settings), along with the qualitative assessment of material characteristics. The attribute ratings, as well as the qualitative descriptors, are used to assess sensory qualities and generalise their influences on material perception. It is observed that respondents refer to past material experiences to define materials, especially the ones with uncertain attributes. While visual/tactile inconsistencies are a hallmark of natural products, such irregularities in materials with evidence of human interaction (e.g., weaving, geometric patterns) lead to poor perception of beauty and value. Fibreness is a strong signifier of naturality, and warm & earthy tones reinforce this perception. Perception of beauty and value is influenced by both visual and tactile attributes, pointing to their bimodal nature; this also emphasises the role of sensory characteristics in creating desirable biobased composites.

Biobased composites, which are sustainable alternatives to fossil-based raw materials could gain acceptance in high-value products if their perceptual handicaps could be overcome. To do this, a deeper understanding of material-attribute relationships and the role of various senses in the formation of biocomposite perception needs to be established. This paper focuses on the role of tactility in contrast with visual stimuli and examines the perceptual qualities that are influenced by tactility. This receives extra attention in e-commerce, which only provides a visual representation of materials/products for the consumers to perceive. The semantic differential method was used to assess users’ perception of various material-attribute correlations. The analysis revealed a significant impact of tactility in the formation of certain attributes such as naturality, roughness and strength, while attributes like beauty and complexity remain less affected and visual-dominant. A clustering analysis revealed higher accuracy in identifying material characteristics in visual-tactile mode. This study also revealed that tactility is a key influence in the perception of naturality, and hence marketing plans for products with eco-credentials could benefit from strategies highlighting and promoting their tactile characteristics. This could also help product designers select the ideal biobased composite suited to communicate desired perceptual qualities.

Biobased composites, which are considered a sustainable alternative to plastics, are yet to create a significant influence on product design and manufacturing. A key reason for this is perceptual handicaps associated with biobased composites and this study was aimed at understanding the mechanisms behind biocomposite perception, in the context of digital visuals. This study of digital biocomposite visuals demonstrated that material perception is influenced by the visual characteristics of the material. Data analysis of the perceptual attributes of the materials pointed towards clear ‘clustering’ of the materials against these attributes. Analysis shows that visual features like fibres and surface appearance may impact aesthetic and functional evaluation and there is no effect on age, gender or polymer type. We also propose a reference framework to categorise biobased composites based on visual order.

Biobased composites offer unique properties in the context of sustainable material production as well as end-of-life disposal, which places them as viable alternatives to fossil-fuel-based materials. However, the large-scale application of these materials in product design is hindered by their perceptual handicaps and understanding the mechanism of biobased composite perception, and its constituents could pave the way to creating commercially successful biobased composites. This study examines the role of bimodal (visual and tactile) sensory evaluation in the formation of biobased composite perception through the Semantic Differential method. It is observed that the biobased composites could be grouped into different clusters based on the dominance and interplay of various senses in perception forming. Attributes such as Natural, Beautiful, and Valuable are seen to correlate with each other positively and are influenced by both visual and tactile characteristics of the biobased composites. Attributes such as Complex, Interesting, and Unusual are also positively correlated but dominated by visual stimuli. The perceptual relationships and components of beauty, naturality, and value and their constituent attributes are identified, along with the visual and tactile characteristics that influence these assessments. Material design leveraging these biobased composite characteristics could lead to the creation of sustainable materials that would be more attractive to designers and consumers.