Hollow graphitic carbon nanospheres: synthesis and properties Cheng Zhang • Gaurang Bhargava • Michael D. Elwell • Sukesh Parasher • Bing Zhou • Douglas Yates • Isabel Knoke • Ioannis Neitzel • Yury Gogotsi Received: 29 September 2013 / Accepted: 3 October 2013 / Published online: 13 December 2013 Ó Springer Science+Business Media New York 2013 Abstract Hollow-graphitized carbon nanospheres (CNS), also known as nanocapsules (CNC), with inner diameter of 20–50 nm and shell thickness of 10–15 nm were synthe- sized from resorcinol (R) and formaldehyde (F) polymer- ized in the presence of an iron polymeric complex (IPC). IPC acts as a dispersant for the formation of uniform R–F– Fe carbon precursor and provides iron catalyst/template for the formation of CNS. The uniform and narrow particle size ( \ 3 nm) of the IPC ensures reproducible synthesis of uniform final products with unique properties. The mor- phology and structure properties of the CNS have been characterized in detail. CNS is as a promising material for replacing carbon black in high-performance and weight- sensitive applications or for replacing CNT in cost-sensi- tive applications. Introduction Carbon black is one of the most widely used carbon materials, but it has limited use for high-end consumer products. The applications of carbon black are limited because its disordered or amorphous structure leads to low electrical conductivity and insufficient oxidation resistance [1]. In addition, high carbon loading is required to obtain the desired level of conductivity in the fabrication of composite materials [2], which may cause deterioration of the mechanical properties of carbon black containing composites. New carbon-based nanomaterials with highly curved graphitic structures, having well-developed crystalline structures, high electrical conductivity, good thermal sta- bility, and satisfactory oxidation resistance, are highly desirable for a large number of applications [3]. For example, CNTs have attracted much attention due to their unique structural, mechanical, and electronic properties and hence their potential use in commercial products [4–6]. However, the volume of CNT manufacturing remains Electronic supplementary material The online version of this article (doi:10.1007/s10853-013-7796-5) contains supplementary material, which is available to authorized users. C. Zhang (&)  G. Bhargava  M. D. Elwell  S. Parasher  B. Zhou R&D Center of Headwaters Technology Innovation LLC, Lawrenceville, NJ 08648, USA e-mail: chengzhang99@yahoo.com G. Bhargava e-mail: gbhargava@headwaters.com M. D. Elwell e-mail: melwell@headwaters.com S. Parasher e-mail: sparasher@headwaters.com B. Zhou e-mail: bzhou@headwaters.com D. Yates Penn Regional Nanotechnology Facility, University of Pennsylvania, Philadelphia, PA 19104, USA e-mail: dmyates@lrsm.upenn.edu I. Knoke  I. Neitzel  Y. Gogotsi Department of Materials Science and Engineering and A.J. Drexel Nanotechnology Institute, Drexel University, Philadelphia, PA 19104, USA e-mail: Isabel.Knoke@drexel.edu I. Neitzel e-mail: Ioannis.Neitzel@drexel.edu Y. Gogotsi e-mail: gogotsi@drexel.edu 123 J Mater Sci (2014) 49:1947–1956 DOI 10.1007/s10853-013-7796-5