Surface assisted growth of CuSO4 micro- and nano- spheres

Abstract

Under similar conditions, only micro-and nano-spheres of CuSO 4 were observed. Such phenomenon was not observed from solutions of other ethanol soluble salts, such as CuCl 2 , Cu(NO 3 ) 2 , Cu(OAc) 2 , FeCl 2 , FeCl 3 , NiCl 2 , CoCl 2 , NiSO 4 ( Figure 5). However, we cannot rule out the possibility to grow amorphous spheres from these salt solutions by varying the solvent, substrates, temperature, concentration etc., which is under investigation in our lab now. The property of the nano/ microspheres due to their large surface is under investigation as well. Although it is not sure whether the growth of nano-and micro-spheres is a unique phenomenon of CuSO 4 in ethanol, the discovery of the micro/nano-spheres of a salt solution may lead to the development of salt based nano/microspheres and applications of these nano/ microspheres.In conclusion, we have synthesized nano/microspheres of CuSO 4 by using a facile solvent evaporation method. These spheres may have applications in medical and industrial fields. It is a hypothesis that the formation of amorphous CuSO 4 nano/microspheres may be due to relatively faster evaporation of ethanol than other solvents such as water, which resulted in differential stress and distribution of porosity Amorphous micro-and nano-sphere of CuSO 4 were synthesized on silicon or glass surface by evaporating ethanol from a CuSO 4 solution in ethanol. Factors, such as substrate and concentration, on the synthesis of the nano/microspheres were studied. However, few works demonstrated the formation of micro-or nanospheres from water-soluble salt [7] When salts are recrystallized in solvents, the salts typically precipitated out in the form of regular or irregular crystals, which is a common property of salts. In this short communication, we demonstrate the formation of amorphous microand nano-sphere of CuSO 4 on silicon or glass surface by evaporating ethanol from a CuSO 4 solution in ethanol.In our approach, a substrate (glass, silicon, or gold coated silicon plate) was submerged in a 20-mL vial with a 0.5 mL CuSO 4 solution in ethanol in it. Ethanol was allowed to evaporate at ambient temperature. The precipitated CuSO 4 solid on the substrate adopted a spherical shape at nanometer or micrometer dimension (Figure 1), which is a typical character of amorphous particles because of their microstructural isotropy. The amorphous character is also evidenced by the appearance of pimple, raspberry-like surface, in contrary to anisotropic crystalline whiskers corresponding to crystals. Some of the incomplete particles are in the shape of puckered plate, or hemispheres with defect.The micro-and nano-spheres were only observed when ethanol was used. When preparing in DMF and water, irregular cluster of particles was observed from DMF or aqueous solutions (Figure 2).Surface property of substrates also affects the formation of spheres, as evidenced by the observation of spheres on silicon or glass surfaces, but not on gold surface (Figure 3), suggesting the surface property plays a critical role in...