International collaboration development in nanotechnology: a perspective of patent network analysis

International collaboration has played an important role in the development of nanotechnology. Patents encompass valuable technological information and collaborative efforts. Thus, this paper examines international collaboration development in nanotechnology using patent network analysis. The results show that the number of international collaboration nanotechnology patents has increased steadily and the proportion of them of total nanotechnology patents has likewise exhibited an upward trend. USA has always been the most influential participant with largest number of international collaboration patents. Asian countries/regions have shown an obvious increase in the number of international collaboration patents. By contrast, there have shown a generally decline in European countries. More and more countries have become actively engaged in international collaboration in nanotechnology with increasingly closer relationships. Two styles of international collaboration exit: while USA, Germany, UK and Japan collaborate with a wide range of countries/regions; Spain, Israel, Russia, Singapore and Taiwan are more selective in their collaboration partners. Though International collaboration has yet to find global significance in terms of patent citation impacts, it has nevertheless been incremental in improving patent citation impacts for most of the top 20 countries/regions since 2004.