## 1 Introduction  
During the past decades, intensive studies have been focused on synthesis of hybrid nanomaterials that are composed of both inorganic and organic components [1; 2; 3; 4; 5]. Compared to the corresponding pure inorganic or organic materials, the hybrid composites have been demonstrated to have more widespread potential applications due to the improved mechanical [6], thermal [7], electrical [8; 9], and optical properties [10; 11; 12]. Various morphologies of the hybrid nanomaterials have been developed, such as nano-rods, films, and particles [13; 14; 15; 16; 17; 18].  
Polymer/TiO\({}_{2}\)-based hybrid nanomaterials are one of the most common nanocomposites, which are widely applied in medicine [19; 20; 21; 22], lithium batteries [23; 24; 25; 26], UV-screening [27; 28; 29], sensors [30; 31], and hybrid solar cell materials [32; 33; 34; 35]. For most of these applications, the TiO\({}_{2}\) nanoparticles (NPs) are typically used as fillers, which have to be homogeneously dispersed in the polymer matrix. The commonly-used technique for dispersing the TiO\({}_{2}\) NPs in a polymer matrix is through direct blending of the TiO\({}_{2}\) NP dispersion with the polymer solution. The major difficulty of this technique is to avoid agglomeration of the TiO\({}_{2}\) NPs. To this aim, it has been proposed to use living free radical polymerization and to initiate the RAFT or ATRP polymerization from the surface of the TiO\({}_{2}\) NPs in order to enhance the filler-polymer compatibility [36; 37; 38]. However, these approaches, though very efficient at the lab scale, are not attractive for large-scale industrial applications. Non-environmentally friendly organic solvents, typically used for both the TiO\({}_{2}\) NP dispersion and the polymer solution, have to be evaporated in the final preparation of the hybrid materials and devices. In addition, the starting TiO\({}_{2}\) NPs usually have irregular shape and broad size distribution, due to their unavoidable certain degree of agglomeration, which will affect the performance of the final hybrid materials.  
In this work, we propose a different strategy to prepare polymer/TiO\({}_{2}\)-based hybrid nanomaterials, based on conventional emulsion polymerization, as shown in Scheme 1. In particular, we start with the synthesis of primary TiO\({}_{2}\) NPs of \(\sim\)5 nm. We first control their aggregation to form TiO\({}_{2}\) nanoclusters (NCs) of \(\sim\)30 nm, under intense turbulent shear (ITS) generated in a microchannel (MC) device. Then, we distribute the TiO\({}_{2}\) NCs in the monomer droplets of a mini-emulsion, produced again using the ITS. These upon polymerization lead to monodisperse polymer/TiO\({}_{2}\) nanospheres (NSs). The size and TiO\({}_{2}\) content of the NSs can be varied by changing the monomer/TiO\({}_{2}\) ratio, as well as the shear rate in the MC device. Since the produced polymer/TiO\({}_{2}\) NSs are dispersed in water and stabilized by surface charges, they can be easily mixed with a TiO\({}_{2}\)-free polymeric NP dispersion to form a new dispersion, where TiO\({}_{2}\)-containing NSs are homogeneously distributed in the new polymer dispersion/matrix at the nanoscale. The concentration of the TiO\({}_{2}\)-containing NSs in the dispersion can be varied by changing the ratio of the two dispersions. Such obtained water-based dispersions can be applied to form hybrid materials and devices through either drying or coating or (injection and extrusion) molding (after drying and forming powders) or rotomolding. As an example, the proposed strategy has been successfully applied to prepare polystyrene/TiO\({}_{2}\) NSs of about 100 nm in diameter.