Since the term "smart material" originated over 30 years ago, referring to material capable of changing its properties automatically in response to an external stimulus (the stimulus or response may be mechanical, electrical, magnetic, optical, thermal, or chemical), interest in the topic has risen steadily. This trend is shown below by the rising frequency of use of the term in print sources tracked by Google Books (the y axis indicates how often the phrase "smart material" occurs as a percentage of all two word phrases). Today, there are many conferences, journals, and textbooks focused on smart materials.

However, the commercial relevance of "smart materials" as a category of related materials technologies is essentially nonexistent. There are few start-ups and few major corporate R&D efforts specifically targeting the field of smart materials. A search of the global patents corroborates this: we identified just 779 patents (and none before 1991) mentioning the term "smart materials." In addition, unlike most emerging materials (see the Lux Research report "Planning for Ripe Fruit: Materials Innovation Lifecycles as a Predictive Scouting Tool"), the rate of patent activity is spiky and not steadily increasing:

In stark contrast, certain individual types of smart materials have seen extensive commercial development. More than 330,000 patents involve piezoelectric materials, more than 70,000 involve thermoelectric materials, and more than 23,000 involve magnetostrictive materials (patent searches include patents from 1900 through the present day). These materials are ubiquitous in applications ranging from consumer electronics to robotics to laboratory and industrial equipment. There is thus a clear disconnect between how commercial and non-commercial entities view smart materials. On the one hand, there is growing academic and popular interest focused on "smart materials" as a general class. On the other hand, companies are disinterested in the general class but highly interested in particular subsets and types of smart material. This disconnect is critical for understanding this space, and here is why:

• The term "smart materials" is too broad to be instrumentally useful in solving particular commercially relevant problems. The category encompasses solids and liquids, as well as polymers, alloys, ceramics, composites, and nanomaterials. Smart materials range from the piezoceramics in inkjet printers to high performance microelectromechanical systems (MEMS) sensors to shape memory alloys and polymers. Any particular commercial R&D effort will draw on, at most, a couple of the dozens of classes of smart materials. As a result, advances in most branches of the field of smart materials will be irrelevant to most companies actually using or considering using particular types of smart materials.

• Mature classes of smart materials do not need to be part of a larger category to prove their commercial value. Piezoelectric, thermoelectric, and electrochromic materials plainly meet the definition of a smart material by changing their shape, temperature, or color in response to voltage, but producers and users of these materials do not typically bother to mention this point, because everyone involved knows their usefulness.

• The umbrella term "smart materials" serves to increase general awareness and interest in emerging subcategories. Unlike mature smart materials, emerging classes like ferrofluids, shape memory composites, and thermoresponsive polymers each benefit from a generalized interest in smart materials in the form of increased early stage research. Highlighting the connection to more mature smart materials further reinforces the potential of these new materials classes to have large future commercial impact.

We've seen this pattern before. The term "nanotechnology" was similarly hyped for many years, but as companies realized the term included a large number of individually impactful or high-potential technologies with a common scientific feature that were nevertheless functionally unrelated to one another, interest in the general category dropped substantially. Today "nano-enabled products" are a trillion-dollar market (see the report "Nanotechnology Update: Corporations Up Their Spending as Revenues for Nano-enabled Products Increase"), but what matters is whether each individual technology solves a problem, not whether it uses a nanomaterial. Smart materials are the new nano: a "smart material-enabled product" market size would similarly total at least in the high hundreds of billions of dollars, but that figure is not useful until we dissect out the individual materials and their relevance to particular applications. There are many hidden gems to be mined in the field of smart materials research, but finding them will require clients to bring to bear patience, a discerning eye, and a clear sense of what specific functionalities and capabilities will be relevant to their business needs. Lux will begin identifying these hidden gems in our upcoming State of the Market Report on smart materials.

Anthony Vicari is an Analyst for the Advanced Materials Intelligence service at Lux Research, which provides strategic advice and on-going intelligence for emerging technologies. For more information, visit the Lux Research site.