Toward sustainable nanoproducts:: An overview of nanomanufacturing methods

Sustainable development of nanotechnology will inevitably require incorporation of life cycle thinking to analyze environmental impacts of nanomanufacturing. While many concerns have been raised regarding the human and ecological health effects of and benefits from using nanoproducts, relatively little attention has been given to the manufacturing phase. Unlike many conventional manufacturing techniques, nanomanufacturing techniques require unique facility and process design as well as operation and control. Accordingly, the environmental burden of most nanomanufacturing techniques may be more profound than that of many other conventional techniques. This article reports on a comprehensive review of the current state of technologies used in the manufacture of nanostructured materials in order to identify those attributes that contribute to environmental impacts. It provides a preliminary analysis of significant attributes of commonly used nanomanufacturing techniques, including strict material purity requirements, less tolerance for defects, low process yields and material utilization efficiencies, repetitive processing steps, the need for specialized environments (such as high temperatures or cryogenic processing), the use of toxic chemicals and solvents, the need for moderate to high vacuum, the use or generation of greenhouse gases, high energy and water consumption, and the potential for chemical exposure.