Dynamics and structure of patenting carbon nanostructures
As in the innovation chain the patents are preceded by scientific publications, we present a number of bibliometric indicators calculated on the basis of the Science Citation Index Expanded (SCIE). According to Fig.1, the interest in the study of carbon nanostructures continues to increase in the world with the average annual growth rate of the number of scientific publications of 14% over the past seven years. The structure of this growth is characterized by Fig.2, showing the peculiar sunset of the "fullerene era", the flourishing and gradual fading of the "CNT era", the rapid ascent of graphene, and also the low "niche" interest in nanodiamonds and other forms of nanocarbon. It should be noted that during this period there have been significant changes in the geography of researchers: the publications of papers began to be determined by major Asian players (more than 68% in 2015), and China has become an unchallenged leader for the foreseeable future, as its closest pursuer (USA) lags behind in its contribution to 26 percentage points (pp.). Together with the structure, the indicators of scientific impact also began to change, for example, since 2011 China has outstripped the United States, and South Korea has outstripped Germany on the contribution to the top 10% of the most cited publications in this area. Singapore, in turn, has bypassed France and Britain since 2012 in terms of contribution to the top 1% of the most cited publications. Russia was in ninth place in 2015 in terms of productivity, however, according to the average citation of publications, it was only in the fourth ten.
ANALYSIS OF PATENT ACTIVITY BASED ON US PTO AND WIPO PATENTSCOPE DATABASES
The intensity of the transformation of scientific knowledge into patentable results can characterize the following integral ratio: about 4.4 US PTO patents and the same number of PCT WIPO applications per 100 publications in the period of 2000–2016. It is worth noting that carbon nanostructures do not refer to leaders in this case. Large commercial maturity is demonstrated, for example, by lasers, where there were 28 US PTO patents and 17 PCT WIPO applications per 100 publications over the same period. Fig.1 shows that the world's publication and patent activities (according to the US PTO database) grew at almost the same pace, while the dynamics of filing PCT WIPO applications in recent years has become noticeably lagging behind. As it follows from Fig.3 and Fig.4, the thematic structure of the patent results in international databases is mainly determined by the rivalry between CNT and graphene, and if graphene outstripped the CNT in the PCT WIPO applications from 2013, then in US PTO patents they practically equaled only in 2016 year. The remaining types of nanostructures serve only as a background for this rivalry. Fig.5 shows that the thematic structures of publications on carbon nanostructures and filed PCT WIPO applications correlate well enough among themselves.
INVENTIVE ACTIVITY OF RUSSIANS AND STRUCTURE OF PATENTING
The most important international economic bloc with the participation of Russia is the BRICS, which in recent years has significantly increased its inventive activity. For example, the percentage of PCT WIPO applications in which at least one of the inventors is a citizen of one of the BRICS countries increased from 3.8% in 2010 to 17.2% in 2016. For comparison: during the same period the similar share of EU-28 decreased from 23.9% to 19.5%. The locomotive is China. Its citizens are among the inventors in 843 US PTO patents for carbon nanostructures issued in 2000–2016. Further, with a large margin follows: India, Russia, Brazil and South Africa, whose representatives participated in 51, 33, 10 and 1 US PTO patents, respectively. A peculiar indicator of the "donorship" of the country can be considered the share of its patents (on the principle of citizenship of at least one inventor), which are issued to the patent owner of another state. The lowest value of this indicator (6%) is typical for China, the largest (58%) – for Russia, that is, Russians connect the commercial prospects of their inventions with the national business to a much lesser extent than representatives of other BRICS countries.
88.4% of US PTO patents with the participation of Chinese inventors, 74.5% – of Indian inventors, 70% – of Brazilian inventors are devoted to CNTs. The same topic is considered in a single patent, obtained with the participation of inventors of South Africa. At the same time, only 15.2% of patents with Russian participation are devoted to CNTs, the remaining topics are as follows: 42.4% – fullerenes and their derivatives; 18.1% – nanodiamonds; 15.2% – OFNC and 9.1% – graphene. Already with the example of this small sample, the specifics of the interests of Russian inventors in the area under consideration are visible. Among the US PTO patents of the Russian patent owners, the following can be singled out:
• US 6245312 issued in 2001 to the Troitsk Superhard Materials scientific technological centre, which was later transformed into the Technological Institute for Superhard and Novel Carbon Materials (TISNCM), on the method for obtaining superhard fullerite and products based on it;
• US 7867467 issued in 2011 to the Diamond Centre (St. Petersburg), on the method for obtaining nanodiamond;
• US 9090752 issued in 2015 to an individual patent holder from St. Petersburg, on multi-layer carbon nanoparticles of fulleroid type;
• US 9096492 issued in 2015 to an individual patent holder from Nizhny Novgorod, for hydrated n-fullerene amino acids, a method for their production and the development of pharmaceutical compositions based on them;
• US 9254340 issued in 2016 to the Almaz Pharm (Moscow), on the method for obtaining a nanodiamond and glycine conjugate for the delivery of glycine to the body.
On the other hand, US PTO patents with the participation of Russian inventors were issued to such well-known foreign companies as Samsung Electronics (South Korea), Siemens (Germany), Ceram Optec Industries (USA), etc.
According to the sample produced from the database of Rospatent, 1109 patents of the Russian Federation for inventions in the field of carbon nanostructures were issued during the period under review. Their thematic structure (Fig.6) differs significantly from US PTO patents and PCT WIPO applications. For example, the number of patents related to CNTs surpassed the number of patents on fullerenes only in 2009, and the number of patents related to graphene only slightly surpassed the number of patents for nanodiamonds and OFNC in 2016.
From the point of view of forming a business ecosystem, it is important who is the recipient of patents. It can be noted that the share of institutes of the Russian Academy of Sciences, FSUEs and individual patent owners among the selected categories of patent holders has been consistently decreased. On the contrary, universities and foreign companies steadily increased their share (Table). If the first could be a consequence of government measures to create an innovative infrastructure of universities, the second should cause some concern. It should be noted that domestic business, slightly increasing its share in 2008-2013, then again lowered it. 57 patents of the Russian Federation (about 41% of all patents of the corporate sector) were issued in 2013–2016 to the foreign companies such as Gurdian Industries (USA), ExxonMobil (USA), BASF (Germany), Photonics France (France), Koninklijke Philips Electronics (Netherlands), etc. Since domestic business still pays little attention to patenting abroad, foreign companies often become co-owners of patents for inventions involving Russians, as it was in 19 out of 33 US patents and in 30 of 87 PCT WIPO applications. This creates certain risks of leakage of patentable ideas.
POSSIBLE AREAS AND DIFFICULTIES OF COMMERCIALIZATION
Perhaps, none of the other representatives of the nanoworld had so many optimistic expectations for revolutionary changes in the economy and other spheres of human life, as with the triad of "fullerenes – CNT – graphene". However, the realization of the enormous potential of this triad was not as easy and fast as expected .
In Russia, a number of specialized start-ups were established and successfully operated already in the 1990s. Among them, UNICHIMTEK (intercalated graphite compounds) from Klimovsk, St. Petersburg-based ASTRIN-HOLDING (fulleroid carbon nanomaterials), ILIP (materials based on fullerene) and Diamond Centre (ultra-dispersed diamonds), as well as Fullerene Centre (production of fullerenes) from Nizhny Novgorod.
TISNCM, founded in 1995 as the Superhard Materials scientific technological centre, has long been successfully combining fruitful research and development with the patenting and commercialization of its results. The Institute for the first time created a technology for the synthesis of superhard fullerite C60, confirming its priority by obtaining in 2001 a US PTO patent. Later on, it developed methods for producing a superhard composite on the basis of carbon (RU 2491987, RU 2523477, RU 2547485, RU 2556673) for applications in the space and aviation industries, in metalworking, and in the mining industry. In general, the subject matter of Russian inventions is related to a rather wide range of applications of fullerenes and their derivatives, for example, in medicine and pharmaceuticals, laser energy and the production of nonlinear optical media for laser power limiters, insulating materials, solar batteries, display technology, etc.
In recent years, there has been growing interest in the possible use of nanodiamonds in composites, lubricants and as drug delivery vehicles . Russia has historical traditions in the production and use of this material. For example, Diamond Centre has developed a safe and reliable method of nanodiamond synthesis with improved technical, economic and environmental parameters that allows to organize a wide production of the product (RU 2348580 and US 7867467). SKN (Snezhinsk) received the patent RU 2452686 for a device for cleaning and modification of nanodiamond; in addition, it was filed PCT application WO/2008/143554. Altai JSC (Biysk), which organized the first mass production of nanodiamonds in Russia, has seven Russian patents for their application in engineering, chemistry and pharmaceutical industry. Almaz Pharm received three Russian patents (RU 2555350, RU 2560697, RU 2560700) and US 9254340 for systems for the delivery of biologically active substances into the body using nanodiamond. In aggregate, Russian patents cover almost all of the above fields of application of nanodiamonds.
Russian scientists who discovered nanoporous carbon, although they later lost the priority for its production, have a number of inventions concerning its use as sorbents for mercury-containing waste (RU 2522676), for creating radio absorbing materials (RU 2570794), for accumulation of natural gas (RU 2625671), etc.
And, nevertheless, the global trend of the 2000s was CNT and, later, graphene. Russia did not react in time to switch the world's research interest from fullerenes to CNTs. At one time, we could not even provide laboratories with nanotubes of the required quality, which inhibited the research and, through the chain, patent activity . The same applies to graphene. Now, with respect to CNT, the situation is gradually straightening out. In the country there are several manufacturers of multi-walled CNTs, one of which is NanoTechCenter (Tambov). Single-walled CNTs on a scale that provides only research needs, produces Carbon Chg (spin-off company of the Institute of Problems of Chemical Physics of RAS in Chernogolovka). And the OCSiAl (Novosibirsk) recently introduced the TUBALL material with a high content of single-walled CNTs (> 75%) at a cost 50 times lower than products of comparable quality.
OCSiAl deserves special attention due to the stated objectives (mass production of CNTs) and participation of RUSNANO in the project. In addition, in this case, domestic business is actively seeking to enter the international market. The company was founded in 2009 by four individuals. The developer of the original technology for the production of single-walled CNTs is M.R. Predtechensky, a scientist from the Kutateladze Institute of Thermophysics of the SB RAS. The basis was a plasma chemical reactor developed and patented by him in 2000 in Russia (RU 2157060) and in 2005 in the USA (US 6846467). The method of CNT synthesis was patented in 2012–2013 by MCD Technologies from Luxembourg (RU 2478572, US 8137653 and US 8551413). The technology is implemented in a pilot industrial facility for the synthesis of single-walled CNT Graphetron 1.0, which was launched by OCSiAl in 2013 in the Technopark of Novosibirsk Akademgorodok. The plant produces up to 10 tons of nanotubes per year, and the price/quality ratio makes their mass introduction economically feasible. Successful operation of Graphetron 1.0 has shown the possibility of unlimited scaling of synthesis technology. The company offers its product as a nano-additive to the cathode material of lithium-ion batteries, rubber for tire production, composites for car body parts, carbon plastics for the manufacture of sporting goods, etc. Its business model is oriented to the introduction of nano-additives on existing and well-functioning plants. At the same time, in each case, a complex technological issue of uniform dispersion of the nano-additive in the host material must be solved . Assessing the commercial viability of this domestic project, one can not ignore the natural rivalry between CNT and graphene, which has a number of advantages over nanotubes [1, 5]. According to some studies, composites with the introduction of graphene are stronger, more rigid and less susceptible to failure than composites with CNTs . At the time of the start, the OCSiAl management evaluated the temporary "window" for realizing the commercial advantage of its method in 5–10 years, and in the opinion of the chairman of the Management Board of RUSNANO, A. Chubais, project can become a flagship for Russia . Nevertheless, in practice the mass introduction of CNTs faces difficulties. For example, in 2015, the construction of a plant in Tatarstan with the capacity of up to 250 thousand tons of nanoproduct per year was announced for their introduction into the production of automobile tires (Nizhnekamskshina) and petrochemical production (Kazanorgsintez) , but in 2017 this project was no longer mentioned . It is also symptomatic that in 2013 such a large German company, like Bayer, engaged in high-tech polymer materials, refused the large-scale project for the production and use of CNTs.
Many associated the future of electronics with graphene, which has unique properties (strength, flexibility, high electrical conductivity). However, this future may not be so close: in tens of years, the well-known Russian scientist A.Vul  has estimated the possible time for the establishment of graphene electronics. In aircraft building, a possible "graphene revolution" is also only at the stage of experiments and demonstrations .
Thus, the initial boom associated with carbon nanostructures has not yet led to their mass commercialization. Nevertheless, ongoing research is able to suggest ways to overcome existing technological, economic, environmental and other difficulties and barriers for the wide application of these remarkable nanostructures. Russia can participate in international competition, according to A.Vul , focusing on the original ways of producing cheap fullerenes and CNTs, the production and use of nanodiamonds, nanoporous carbon, which factually confirms the conducted patent analysis. Of course, it is necessary to stimulate research on graphene and other 2D materials, since it is at this stage that it is possible to "overtake, not catching up". ■
The work was supported by the Russian Foundation for Basic Research (grant No. 16-06-00009).