Nanoparticle spherical morphology

Thiol-functionalized mesoporous silicas not only serve as a basis for sulfonic acid-functionalized phases, but can be used for several other applications, for instance as adsorbents. Thiol-functionalized silicas can also be prepared as small nanoparticles with spherical morphologies by employing modified Stober reaction conditions.174 The high affinity of these compounds for thiophilic heavy metals, especially toxic Hg2+ ions, has been demonstrated by several authors.175-178... 

The nanoparticles of non-linear optical material KTiOPO< (KTP) were synthesised through metal-organic precursors, prepared by reaction of alkoxides (RO)3P(0), Ti(OR)4, and KOR (R-Et, Pr, Bu) in alcohol solution. The precursor thermal decomposition (650-900°C) resulted in a single-phase KTP of different, preferably spherical, morphology. The dimension of produced particles is ranged from 45-50 up to 800-1500 nm. 

Fig. 2 Transmission electron micrographs and co-registered in vivo optical luminescence (Cherenkov radiation) and X-ray transmission images in tumour-bearing mice (1 h and 24 h post-dose, tumours marked with a circle) of Au nanoparticles of varying morphologies including (a) spheres (b) disks (c) rods and (d) cages. Spherical morphologies show the best performance in terms of blood circulation, clearance and tumour uptake compared with disks, rods and cages. Reprinted with permission from Black et al. ACS Nano, 2014, 8(5) 4385-4394. Copyright (2014) American Chemical Society.

The above examples can be supplemented by several others. However, the point that emerges out of the above is that there are indeed some indications of factors influencing particle shape, but so far they are not enough to lead to an assured product batch of monomorphological nanoparticles (except the spherical morphology), at least not in a general way. The different particle shapes recorded to have been obtained in oxide and non-oxide systems through microemulsions and described below, are assembled in Fig. 5.1. 

The higher levels of control provided by the microreactors over the reaction parameters as compared to the conventional batch method and the production of pure phase copper sulfide nanoparticles in less than 3 seconds makes this method very attractive. The copper(II) complex of 1,1,5,5-tetra-iso-propyl-2-thiobiuret was used as a single source precursor for the synthesis of copper sulfide nanoparticles in a continuous flow process. " The nanoparticles had spherical morphology and were produced either as a pure CU7S4 or CU7S4 with minor impurities of CU9S5. Fig. 8 shows a schematic diagram of the flow reactor used by O Brien et al. ... 

Figure 6.10 Morphology and structure of Ce02 nanoparticle spherical aggregates prepared with ILs. (a) SEM image, (h) TEM image, (c) HRTEM image, (d) Schematic. Reprinted with permission from Li et aJ Copyright 2008 the American Chemical Society.

This species has been used as precursor of nanogold particles by electrodeposition. When the electrodeposition is induced from the isotropic state at 117 °C, the nanoparticles obtained are nanodots aggregated in a spherical-like shape. In contrast, the morphology of the nano particles prepared from the SmA mesophase at 111 °C consist of leaf-like forms interlocked in rosettes. 

In general, the various synthesis strategies for nanocarbon hybrids can be categorized as ex situ and in situ techniques [3]. The ex situ ( building block ) approach involves the separate synthesis of the two components prior to their hybridization. One can rely on a plethora of scientific work to ensure good control of the component s dimensions (i.e. size, number of layers), morphology (i.e. spherical nanoparticles, nanowires) and functionalization. The components are then hybridized through covalent, noncovalent or electrostatic interactions. In contrast, the in situ approach is a one-step process that involves the synthesis of one of the components in the pres-... 

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