An evolutionary process of global nanotechnology collaboration: a social network analysis of patents at USPTO

Using social network analysis to examine patenting data available at the USPTO, this paper explores an evolutionary process of global nanotechnology collaboration network from the perspective of entry and exit of collaborative organizations (nodes) and network’s preferential attachment process. The results show that the nanotechnology collaboration network evolved through frequent updates of the nodes and their relations (links). Compared with degree centrality and closeness centrality, betweenness centrality of an existing node was a significantly better predictor of the preferential attachment. The nodes with higher betweenness centrality were more influential to attract other nodes. This fact is observed while the network evolved. The results reveal that the core nodes with higher betweenness centrality were mostly large organizations that were equipped with core technology. They played an important broker role attracting more organizations into collaboration.