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<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">Front. Mater.</journal-id>
<journal-title>Frontiers in Materials</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Mater.</abbrev-journal-title>
<issn pub-type="epub">2296-8016</issn>
<publisher>
<publisher-name>Frontiers Media S.A.</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.3389/fmats.2017.00038</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Materials</subject>
<subj-group>
<subject>Specialty Grand Challenge</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Grand Challenges in Translational Materials Research</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author" corresp="yes">
<name><surname>Kordas</surname> <given-names>Krisztian</given-names></name>
<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
<xref ref-type="corresp" rid="cor1">&#x0002A;</xref>
<uri xlink:href="http://frontiersin.org/people/u/437904"/>
</contrib>
</contrib-group>
<aff id="aff1"><sup>1</sup><institution>Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu</institution>, <addr-line>Oulu</addr-line>, <country>Finland</country></aff>
<author-notes>
<fn fn-type="edited-by"><p>Edited by: Jon Ajuria, Ikerlan, Spain</p></fn>
<fn fn-type="edited-by"><p>Reviewed by: Josep Albero, Institut of Chemical Technology (CSIC-UPV), Spain</p></fn>
<corresp content-type="corresp" id="cor1">&#x0002A;Correspondence: Krisztian Kordas, <email>krisztian.kordas&#x00040;oulu.fi</email></corresp>
<fn fn-type="other" id="fn001"><p>Specialty section: This article was submitted to Translational Materials Science, a section of the journal Frontiers in Materials</p></fn>
</author-notes>
<pub-date pub-type="epub">
<day>21</day>
<month>11</month>
<year>2017</year>
</pub-date>
<pub-date pub-type="collection">
<year>2017</year>
</pub-date>
<volume>4</volume>
<elocation-id>38</elocation-id>
<history>
<date date-type="received">
<day>01</day>
<month>09</month>
<year>2017</year>
</date>
<date date-type="accepted">
<day>31</day>
<month>10</month>
<year>2017</year>
</date>
</history>
<permissions>
<copyright-statement>Copyright &#x000A9; 2017 Kordas.</copyright-statement>
<copyright-year>2017</copyright-year>
<copyright-holder>Kordas</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/"><p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.</p></license>
</permissions>
<kwd-group>
<kwd>nanotechnology</kwd>
<kwd>energy applications of nanomaterials</kwd>
<kwd>microelectronics</kwd>
<kwd>nanoelectronics and optoelectronics devices</kwd>
<kwd>chemical engineering</kwd>
<kwd>biotechnology</kwd>
<kwd>environmental engineering</kwd>
<kwd>sustainability</kwd>
</kwd-group>
<counts>
<fig-count count="0"/>
<table-count count="0"/>
<equation-count count="0"/>
<ref-count count="46"/>
<page-count count="4"/>
<word-count count="3086"/>
</counts>
</article-meta>
</front>
<body>
<sec id="S1">
<title>From Discoveries to Commercialization</title>
<p>Technological progress in our modern society is driven by discovery and deployment of innovation in materials synthesis, design, and application. As such, research related to &#x0201C;Translational Materials,&#x0201D; which are capable of revolutionizing the growth of our civilization play pivotal roles. A key thrust, therefore, should be geared toward the development of novel, innovative, and practical solutions that tackle challenges (Hayden, <xref ref-type="bibr" rid="B10">2014</xref>). The continuous demand for having smaller, better, stronger, lighter, more durable, and efficient tools and devices often with complex functionalities requires a novel approach to advanced materials and design. While materials research is a rather broad field of science and technology, encompassing various disciplines ranging from biotechnology to electronics, and information technology, what makes translational materials research particularly important is the way of thinking and answering a question: How can we translate advances and move ahead toward commercialization? Obviously, it is not the first question what a scientist considers when working on a new topic. Maybe at the time of discovery, there is no technology yet to implement the theory in practice or to scale up a laboratory experiment to a pilot or industrial production. However, great inventions and discoveries shall and will find the way and this is what we ought to contribute to in our Translational Materials Science section of Frontiers in Materials.</p>
<p>Historically, the most important man-made materials were those used in construction, transportation, weapons and clothing, etc., putting much weight on the manufacturing of materials such as glasses, ceramics and their composites, metal alloys, and fibrous materials of natural origin. Later, in the twentieth century, the revolutionary results in physics, chemistry, and biology led to the birth of modern materials science, and let us build industries without which we cannot imagine our life as we know it today. Such development has played a key role by providing right impetus to food and pharmaceutical industries, as well as to electronics and information technology. The extremely rapid development of these latter two is unprecedented considering that the first transistor was made in 1947, and the semiconductor industry today has total annual revenue of more than 300 billion USD<xref ref-type="fn" rid="fn1"><sup>1</sup></xref> supplying components and parts for all kinds of electrical appliances.</p>
</sec>
<sec id="S2">
<title>A Contemporary Example of a True Translational Material: Carbon-Based Nanomaterials</title>
<p>Because of the broad spectrum of materials in science and technology, the number of potentially viable new materials and associated technologies is enormous, making it impossible to provide a complete review within a single article. Here, we give only a few examples to demonstrate how new nanomaterials based on carbon nanostructures could revolutionize some selected fields in electronics, energy, chemical, and environmental applications. Since the discovery of fullerenes (1985), carbonaceous materials have their renaissance, which was boosted even further after finding carbon nanotubes (1991) and later graphene (2004) and their derivatives making up a business of approximately one billion USD in 2016 only of carbon nanotubes<xref ref-type="fn" rid="fn2"><sup>2</sup></xref> used in sporting goods, battery/capacitor electrodes, in different parts of vehicles but also in electrical displays among others.</p>
<p>Carbon nanostructures may be synthesized by a number of different methods that are easy to scale up to produce massive amounts of materials at reasonable cost (Ajayan, <xref ref-type="bibr" rid="B2">1999</xref>). Although hydrocarbons are applied as typical precursors to grow carbon nanotubes (Colomer et al., <xref ref-type="bibr" rid="B6">2000</xref>), nanofibers (Huang et al., <xref ref-type="bibr" rid="B11">2002</xref>), and graphene (Chae et al., <xref ref-type="bibr" rid="B5">2009</xref>) on catalytic surfaces using chemical vapor deposition, one may also apply renewable raw materials such as alcohols or any other naturally occurring organics (hydrocarbons, aldehydes, or carboxylic acids, e.g., from distillation fractions of plants) (Maruyama et al., <xref ref-type="bibr" rid="B21">2002</xref>; Kumar and Ando, <xref ref-type="bibr" rid="B17">2005</xref>; Ghosh et al., <xref ref-type="bibr" rid="B8">2009</xref>; Seo et al., <xref ref-type="bibr" rid="B33">2017</xref>). Carbon nanostructures are interesting for many reasons. Made of carbon, in which the atoms are held together with strong covalent bonds, these nanostructures are of light weight and mechanically strong. While structures with large sp<sup>3</sup> hybridized carbon fraction such as in diamond-like carbons display extreme hardness, poor electrical but excellent thermal transport; sp<sup>2</sup>-hybridized structures (e.g., carbon nanotubes and graphene) are typically flexible and show structure (and chirality)-dependent electrical behavior taking metallic, semi-metallic, or semi-conducting forms (Loiseau et al., <xref ref-type="bibr" rid="B20">2006</xref>).</p>
<p>Owing to the colorful surface chemistry of nanostructured carbons, practically any functional group can be introduced and thus these materials may be grafted in all kinds of polymers allowing for light-weight structural, thermal, and electrical composites with enhanced features (Spitalsky et al., <xref ref-type="bibr" rid="B36">2010</xref>). Dispersions of functionalized nanotubes and graphene in various solvents (Kordas et al., <xref ref-type="bibr" rid="B14">2013</xref>) used as conductive inks are suitable for printing (Kord&#x000E1;s et al., <xref ref-type="bibr" rid="B15">2006</xref>) and spray coating applications (Kaempgen et al., <xref ref-type="bibr" rid="B13">2005</xref>) to replace costly silver based inks and indium tin oxide coatings. This latter application is particularly important since our indium resources are becoming rapidly depleted due to the excessive use in transparent conductive touch screen panels and photovoltaic device electrodes (and improper recycling of related e-waste) making any alternative materials and technologies industrially indeed very relevant (Mohl et al., <xref ref-type="bibr" rid="B24">2015</xref>; Werner et al., <xref ref-type="bibr" rid="B43">2015</xref>).</p>
<p>When spun in microscopic fibers similar to the yarns in the textile industry, one obtains mechanically robust carbon nanotube microfiber cables with practically any length (Dalton et al., <xref ref-type="bibr" rid="B7">2003</xref>) and may be, some day, even realize the vision of Richard Smalley about &#x0201C;space elevators.&#x0201D; While the electrical conductivity of such nanotube fibers is not sufficient to directly replace ordinary metals (Al and Cu) in power electronics, however, after doping them with alkali metals or halogens, the mass normalized electrical conductivity has been shown to become comparable to those of good conductors (Salvato et al., <xref ref-type="bibr" rid="B32">2001</xref>; Zhao et al., <xref ref-type="bibr" rid="B46">2011</xref>). Having that accomplished, such doped macroscopic nanotube fibers suggest new perspectives for electrical cable manufacturers in the future. Another related interesting application is in traditional incandescent bulbs to replace tungsten, taking a few steps back to the roots, and reinvent carbon based filaments again (Wei et al., <xref ref-type="bibr" rid="B42">2004</xref>).</p>
<p>Robust macroscopic carbon nanostructures and their hierarchical composites that combine various forms of carbon foams, nanotubes, and graphene offer ideal multipurpose monolith-type materials for diverse applications. These large specific surface area materials with light-weight and porous structures (even with multimodal porosity) are excellent absorbers of fluids finding use in chemical separation and environmental engineering (Pham et al., <xref ref-type="bibr" rid="B28">2014</xref>). When decorating the surface of carbon with metal, metal oxide/sulfide nanoparticles, the structure becomes catalytically active resulting in new types of catalyst beds suitable for all kinds of chemical reactors (Serp et al., <xref ref-type="bibr" rid="B34">2003</xref>; Halonen et al., <xref ref-type="bibr" rid="B9">2010</xref>). By exploiting the electrical conductivity, in conjunction with the already mentioned advantageous properties, we end up in electrodes for electrochemical sensing (Sainio et al., <xref ref-type="bibr" rid="B31">2015</xref>), energy conversion (Pham et al., <xref ref-type="bibr" rid="B29">2017</xref>), storage (Talapatra et al., <xref ref-type="bibr" rid="B38">2006</xref>; Pushparaj et al., <xref ref-type="bibr" rid="B30">2007</xref>), and harvesting (Aitola et al., <xref ref-type="bibr" rid="B1">2011</xref>).</p>
<p>A number of further applications have been demonstrated, and some of them are still in the pipeline waiting for exploitation and commercialization such as CMOS compatible field-emitters with high current density and low turn-on field (Sridhar et al., <xref ref-type="bibr" rid="B37">2014</xref>), gas detectors (Modi et al., <xref ref-type="bibr" rid="B23">2003</xref>), vertical and horizontal interconnects in integrated circuits (Li et al., <xref ref-type="bibr" rid="B18">2003</xref>; Wei et al., <xref ref-type="bibr" rid="B42">2004</xref>; Wang et al., <xref ref-type="bibr" rid="B41">2011</xref>; Kord&#x000E1;s et al., <xref ref-type="bibr" rid="B15">2006</xref>), soft electrodes (Toth et al., <xref ref-type="bibr" rid="B39">2009</xref>), heat conduction and dissipation elements in electronics packaging (Kord&#x000E1;s et al., <xref ref-type="bibr" rid="B15">2007</xref>; Liu et al., <xref ref-type="bibr" rid="B19">2009</xref>), and so forth.</p>
</sec>
<sec id="S3">
<title>The Grand Challenges in Discovery and Development of Translational Materials</title>
<p>The list of applications with high potential and commercial relevance may be continued, and this is just an example of nanostructured carbons. Emerging classes of fascinating materials including new multifunctional electroceramics and glasses (Setter and Waser, <xref ref-type="bibr" rid="B35">2000</xref>; Bai et al., <xref ref-type="bibr" rid="B4">2017</xref>), synthetic (Ikkala and ten Brinke, <xref ref-type="bibr" rid="B12">2002</xref>; Noriega et al., <xref ref-type="bibr" rid="B26">2013</xref>), and biopolymers (Van de Velde and Kiekens, <xref ref-type="bibr" rid="B40">2002</xref>; Petersson and Oksman, <xref ref-type="bibr" rid="B27">2006</xref>), layered materials (Mas-Balleste et al., <xref ref-type="bibr" rid="B22">2011</xref>; Muchharla et al., <xref ref-type="bibr" rid="B25">2013</xref>), metamaterials (Zhang and Liu, <xref ref-type="bibr" rid="B45">2008</xref>; Yu and Capasso, <xref ref-type="bibr" rid="B44">2014</xref>) among many others expand the list of applications.</p>
<p>However, the key to the long-term success of development and deployment of Translational Materials is complex. First, one of the major bottlenecks is the lack of strategic collaboration and information exchange between academia and industry. These key players need to make sure that there is a common understanding on what academic scientists can offer and how industry research and development can propel it further to achieve competitive products. Second, funding agencies shall understand that ground breaking &#x0201C;applied&#x0201D; science is often the result of a thorough &#x0201C;fundamental&#x0201D; scientific investigation, where sometimes incremental research results can point in to the right direction. Such sentiments can bridge the gap between innovations and practical applications and make the road toward success a little less bumpy. There can be excellent discoveries, without sufficient funding, the promising results of basic research often will not be able to grow further to bring the fruits. Third, and very importantly, any development shall be made through considering sustainability with all its ingredients including energy efficiency as well as smart usage of abundant and renewable materials to preserve our nature and environment (Anonymous, <xref ref-type="bibr" rid="B3">2017</xref>). While recycling and the overall idea of circular economy offer a momentary solution to extend the period of availability of even scarce elements, the efficiency of return is never 100%, which inherently results in loosing valuable raw materials and gradual depletion of our globe&#x02019;s resources.</p>
<p>Accordingly, new technologies and materials are in constant need to complement or preferably replace old ones while maintaining or even improving the particular functionality, yet offering environmentally friendly alternatives to conventional materials keeping both academia and industry busy for the upcoming years to work on translational research.</p>
</sec>
<sec id="S4" sec-type="author-contributor">
<title>Author Contributions</title>
<p>KK compiled and written the manuscript.</p>
</sec>
<sec id="S5">
<title>Conflict of Interest Statement</title>
<p>The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
</body>
<back>
<ack>
<p>The author thanks Professor Saikat Talapatra (Southern Illinois University, Carbondale) and Professor Robert Vajtai (Rice University, Houston) for fruitful discussion and suggestions on the manuscript.</p>
</ack>
<fn-group>
<fn fn-type="financial-disclosure">
<p><bold>Funding.</bold> Funding received from the Academy of Finland (Suplacat) and University of Oulu (MtM RC) are acknowledged.</p></fn>
</fn-group>
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