Employing Ashby Material Selection Diagrams in Sustainable Nano-Enabled Product Design

As the use of nanomaterials in products continues to increase, it is becoming more important to understand the relationship between the functional performance of these materials, their negative implications to human health and... [ view full abstract ]

As the use of nanomaterials in products continues to increase, it is becoming more important to understand the relationship between the functional performance of these materials, their negative implications to human health and the environment, and how they compare against more traditional non-nanomaterials. However, different stakeholders, such as a regulatory agencies and producers, may value a material's performance or implications differently. To introduce nanomaterials in a consistent way to all stakeholders, we propose modifying a well-established tool from the material science literature, Ashby Material Selection Charts.

Ashby Material Selection Diagrams have long been used in bulk material selection based on a consistent performance index, such as strength, flexibility or thermal conductivity. These performance indices were often compared against a negative index, such as cost/kg or density, with the goal being the optimization of the positive and negative indices. These charts, while very simple and easy to use, usually focus on bulk materials with more easily defined indices. They have recently been used for nanomaterials with easily defined indices and for bulk materials with environmentally relevant indices. However, if material scientists and product designers want to make more sustainable choices moving forward, it will be important to bridge the gap between these scientists and environmental scientists with charts that address nanomaterials, bulk materials, and more sustainability-based indices. 

To further our proposal for the utilization of sustainable nanomaterial selection charts, we have performed a case study on traditional antimicrobial agents, antimicrobial nanomaterials, and conductive nanocomposites. We compared their performance based on their antimicrobial activity and electrical conductivity with the negative implications of cost, cradle-to-grave embodied energy and toxicity to create five 2-dimensional sustainable nanomaterial selection charts to be used by product designers, as well as a total of seven 1-dimensional charts. We also discuss the various modifications that can be performed during manufacturing to lessen the negative impacts or improve performance so emerging nano-enabled products can perform as well as traditional materials, while also acting as a more sustainable solution.