Carbon nanospheres were synthesized using sol-gel processing of organic and aqueous resorcinol formaldehyde (RF) sols combined with electrospraying technique. RF sol was electrosprayed to form nanodroplets which were collected on a Si wafer. After oven drying at 60°C for 12 h, RF nano-droplets were pyrolyzed at 900°C in an inert atmosphere to yield the carbon nanospheres. This study reports the optimization of various process parameters including needle diameter, applied electric potential and liquid flow rate in order to get spherical, mono-disperse particles. For the organic RF sol, the optimized parameters, needle diameter 0⋅241 mm, electric potential, 1⋅5 kV/cm and a flow rate of 0⋅8 ml/h, enabled the synthesis of nearly monodispersed carbon nano-spheres with diameter of 30⋅2 ± 7⋅1 nm. With the same conditions, aqueous RF sol produced irregularly shaped nanoparticles with a smaller mean diameter and much higher variance (17⋅4 ± 8⋅0 nm). The surface properties were significantly influenced by the surface morphologies as demonstrated by the water contact angle (WCA) studies. The surface covered with the RF derived carbon nano-spheres was extremely hydrophilic (WCA 10⋅1°) as compared to a much weaker hydrophilicity of the RF derived carbon films (WCA 83⋅3°). The hydrophilic carbon nanospheres reported here may have potential applications as adsorbents and in controlled drug delivery, biosensors and carbon-based microelectromechanical systems (C-MEMS) including bio-MEMS.

PurposeThe purpose of this paper is to examine the dividend payout behavior of Indian firms and test whether the three prominent dividend policy theories (signaling, life-cycle and catering) explain the dividend policy of Indian firms.Design/methodology/approachThe authors test the three theories using the methodology based on the studies of Nissim and Ziv (2001), DeAngelo et al. (2006) and Baker and Wurgler (2004). For testing the signaling theory, the authors regress the change in earnings on the rate of change in dividends using the pooled and Fama–Macbeth regressions. The life cycle theory is tested by running a logistic regression of the dividend payment decision on two proxies of life-cycle measured by the ratio of earned to total equity. Finally, the catering theory tests the relationship between the decision to pay a dividend and the dividend premium.FindingsThe results based on a sample of Indian firms from 1992 to 2017 show that the dividend policy of Indian firms can be explained using the life-cycle theory. However, there is no evidence in support of the signaling and catering theories.Originality/valueIt provides insights into the dividend policy of Indian firms. Though there have been a few studies examining the dividend payout in India, none of the existing studies tests these theories of dividend payout. The existing research using the Indian data provides indirect evidence about the life-cycle theory. This study is the first one to test the application of these theories for Indian firms.

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