Materials in Design

In this chapter we begin to look more directly at the use of new nanomaterials and nanotechnologies in design. There are already many applications of nanomaterials in design, and more are expected soon. We look at these topics from the perspective of designers and within the larger cultural-socioeconomic

context in which designers operate.Making effective design application use of new scientific findings that seemingly appear every day within the nanomaterial field is not as easy as might first appear. History is replete with examples of seemingly fabulous scientific discoveries that surely seemed to the discoverers to have huge potential applications in many areas, only to have them lie idle for many years or not be developed at all. Reams of studies in fields such as technology transfer have looked into why this is so. Reasons vary widely but are rarely of any surprise to individuals working in a real-world development context. Design ideas may often be simply naïve, or design objectives can be confused or unclear. Target markets or user audiences may be undefined or unclear, nonexistent, or simply not large enough to be of commercial interest. Other existing products may already accomplish similar desired ends better or in a more costeffective way than the proposed product. Proposed products may never have been benchmarked against existing products. There

might not be adequate test results to convince anyone of the efficacy of the product. Actual manufacturing processes for converting a science-based finding into implemental technology suitable for use in a commercial environment may either not be actually feasible or be cost-prohibitive (or not yet explored enough to know).

There may be legal or institutional barriers that would prevent active consideration of a new product or cause an interested developer to think twice before proceeding. There can be user resistance from sources that should have perhaps been anticipated but perhaps were not (e.g., environmental health hazards in using new

materials) or come from sources that simply could not have been easily anticipated a priori. The list can go on and on. In thinking about how we might use nanomaterials in design, it is useful to step back considerably and not define the issue simply as a technology-transfer problem—a self-limiting approach—but rather to think about it first in more fundamental terms. What is the role of materials in design? How do material properties influence the shape or form of objects and environments? What are we trying to do when we are using a specific material? On what basis do we compare nanomaterials to other high-performance materials?

Do we really expect new products to be made of just nanomaterials, or if not, what specific role do we expect them to play? In what kind of product or building system might they be best

used? What can we hope to accomplish? The first of these questions is by no means new. Questions surrounding the way an artifact or environment has been conceived, how it was made, and the materials of which it has been made have been a particular preoccupation of designers, engineers, and builders for ages. An understanding of the potential benefits and limitations of various materials is clearly evident in early works of art, architecture, and engineering . Examples abound. Medieval builders, for example, are often said to have clearly understood the properties of stone, and they used this knowledge to help shape the arches and vaults of history’s great Romanesque and Gothic cathedrals. But what is exactly meant here by this kind of reference? Is it that the knowledge of certain properties of stone— that it is quite strong when carrying forces that cause compression within it and relatively weak when subjected to forces that cause tension to develop—somehow led directly to the creation of these complex cathedrals as we now see them? Clearly this direct line of thinking—a form of technical determinism—is highly suspect in this example, to say the very least. We do know that the use of arches and vaults, which we now know to naturally carry internal forces by

a compression action, has been known since antiquity to be a good way of spanning large spaces with stone and would sensibly have been used by Medieval builders, and that this knowledge was clearly fundamental in the development of history’s great cathedrals, but it was obviously only one of many contributing factors in a landscape of complex reasons that range from the symbolic to the societal and cultural. We thus need to keep in mind that the nature of our world of designed objects and environments is not dictated by a consideration

of the technical properties of a material alone, no matter how fascinating they might be; but it is equally important to acknowledge their fundamental role—we know that the introduction of new materials with improved technical properties has also led to innovative new designs . From the point of view of this book, the best approach to understanding the use of materials in design remains through an examination of the benefits and limitations associated with the specific properties of materials. For this initial discussion, material attributes can be very broadly thought of in terms of their technical properties that stem from the intrinsic characteristics of the material itself (its density and its mechanical, thermal, optical, and chemical properties); their perceptual qualities that stem from our senses (sight, touch, hearing, taste, smell); and those culturally dependent qualities that fundamentally stem from the way our society or culture views materials. The intrinsic characteristics of materials are dependent primarily on the fundamental atomic structure of the materials and are discussed extensively in Chapter 4. Typical technical properties include failure strengths, elastic moduli values that relate deformations to stress levels, electrical conductivities, thermal conductivities, and a host of other measures related to the mechanical, optical, thermal, and chemical qualities of materials . Clearly, these kinds of properties are of fundamental importance to an engineering perspective on the use of materials in the context of designing products or buildings, and we can expect that work in the nanomaterials field can lead to dramatic improvements in these kinds of properties. At the moment, the important point here is simply that they intrinsically result from a material’s internal structure and are not dependent on any kind of societal or cultural view of the material. The perceptual qualities of a material relate to the way humans perceive them in terms of our basic senses. Visual qualities stem from a combination of specific characteristics such as transparency, translucency, opaqueness, reflectivity, and the texture of the surface (which in turn produces glossy, matte, or other appearances). Tactile qualities related to the sense of touch stem the texture of the surface—whether it is rough or smooth, its relative hardness or softness, and the feeling of warmth or coldness experienced. The qualities of materials that relate to our sense of hearing have to do with the kind of sounds—dull, sharp, ringing, muffled, low or high pitch— produced when the material is set in a vibrational mode, including by simply striking it. The sound of a metal object striking a sheet of lead is quite different than when it hits a piece of glass. In some design situations, the senses of smell or taste can be important as well. Certainly these qualities are directly related to the intrinsic properties and structure of a material. Polycrystalline materials are normally opaque or translucent because of the way light impinging on them is scattered. The sense of warmth or coldness depends on the way heat is conducted away at the point of touch, which in turn depends on both the thermal conductivity and specific heat of the material. We look at these kinds of relationships in more detail in Chapters 4 and 5. For the moment, what is important to note is that there is a basis for these qualities in the intrinsic properties of the material. But here we should also note that the way we ultimately perceive these same qualities in a neurological sense is also dependent on our own receptive mechanisms. The spectrum of light that is visible to humans or the sound wavelengths we can hear, for example, are quite different than for other animals. What we actually perceive can be quite a complex topic. We can still note, however, that since these qualities that relate to the senses remain in some way linked

to specific mechanical, thermal, optical, or chemical properties, enhancing or otherwise modifying these qualities through the use of nanomaterials is entirely possible. Thus, the sense of warmth on touching a surface might be enhanced using nanomaterials to modify the thermal conductivity and/or specific heat of the surface

material. The associative qualities of a material are placed on it by both its use context and its users . As such, these characteristics are coupled with the context in which a material is found or used, and consequently, are ultimately dependent on the view of both individuals and society toward these materials, which are in turn culturally dependent. Specific examples are abundant and obvious here. For one, diamond is a material possessing many highly interesting intrinsic and technically oriented properties that make it extremely attractive for use in many circumstances in which extreme material hardness—an intrinsic property—is desired, as is

the case in many industrial processes. At the same time, diamonds clearly possess many associative qualities placed on them by our culture and society that are fundamentally symbolic but nonetheless of real importance.

The role of diamond jewelry in our society, for example, is fascinating. Yet even here, intrinsic properties of diamonds remain relevant. Humans are fascinated with the stunning color characteristics that we see when we peer into the material itself. This effect is in turn directly related to the material’s high index of refraction. As another example, we also see associative qualities present in the many synthetic materials that were historically widely introduced and used as substitutes for more expensive materials (for example, various synthetic materials introduced for flooring, such as linoleum, or for kitchen countertops). In some instances, these materials often became viewed as exactly that—cheap substitutes—no matter whether their physical properties are superior to those of the original or not. (Many technical properties of some new synthetics are

indeed superior to common traditional materials.) In other cases, such as with the introduction and use of Bakelite in early radio housings, there were few negative perceptions of this type because the synthetic material came almost immediately to be associated with exciting new technological advances and wonderful new emerging lifestyles that allowed broad connectivity to the world at large . Countless other examples exist. Understanding and dealing with these associative qualities is an important part of a designer’s role in dealing with objects used by the population at large.

Societal health concerns with the use of materials were not a terribly important consideration in describing or selecting a material until fairly recent years, when the impact of material selection on human health became better understood. We now know that the outgassing of materials within closed environments, for example, can produce a form of indoor air pollution that can cause occupant sickness. Nanomaterials are seen by some as posing potential health threats but by most others as a way of reducing them . Issues of sustainability and general environmental concerns span the spectrum from notions of how much embodied energy is used to produce a material all the way through its susceptibility to recycling are, again, responsive to societal concerns and mandates. Economic concerns, including the literal cost of a material, are everpresent. Costs of nanomaterials are known to be extremely high, which in turn suggests that they be selectively used. Both initial and long-term or life-cycle costs are important, but again these are values placed on the materials by their use in our society and our culture. There are also many forces for change that are strong drivers for new

product forms. illustrates some of these driving forces at a very broad level. Many are opportunity based and evolve from either changing population characteristics or the availability of new technologies

that allow needs to be met that could not be met before. Indeed, in many instances nanotechnologies are expected to be disruptive technologies that radically alter product forms. In other cases, nanomaterials and nanotechnologies will afford continuous improvement opportunities. Other broad forces for change can be

characterized as concern driven. These include a wide array of issues relating to the environment, national security, and so forth. Many new products have been spawned in response to concerns of this

type. In both opportunity- and concern-driven forces, a remarkable range of new scientific understandings contribute to the evolution of new or significantly adapted products. Given that externally based qualities are dependent on societal and cultural values, it is likewise to be understood that there is no uniform agreement on the relative importance of these different qualities, as is evidenced by the intense societal debates that still occur over recycling. Though reuse of materials has been accepted as a value by broad segments of our society, anyone can still go into any store and buy products that are fundamentally designed to be cast away after use, made from materials deliberately chosen with disposability rather than recycling in mind. These societal debates are ultimately played out in very specific material choices. It is the outcome of these debates over broad societal and cultural values, however, that provides impetus for some of the greatest forces for

change in the development and selection of materials.