Polymer/Laponite Composite Latexes: Particle Morphology, Film Microstructure, and Properties

Abstract

Transparent film materials with excellent mechanical and thermal properties were elaborated by drying a latex suspension of armored polymer/Laponite composite particles. Low‐temperature TEM observation of ultrathin cross‐sections of the films indicated a unique network morphology characterized by a “honeycomb” distribution of the Laponite platelets remindful of the original particles morphology.magnified image

Design and fabrication of colloidal polymer nanocomposites

“…Bourgeat-Lami et al have used organically-modified laponite clay as seeds for emulsion polymerization and thereby prepared various colloidal hybrids with clays located at the polymer particle surfaces [117][118][119]. The processing conditions affected the particle morphology and latex stability.…”

“…[119] An example of using polymer colloids as a template is shown in Figure 13b [101]. In this case, surface hetero-flocculation was used to encapsulate PS particles with single-wall carbon nanotubes.…”

Síntese de nanocompósitos com propriedades anisotrópicas via polimerização radicalar controlada em emulsão

“…A variety of polymers can be prepared by ATRP technique, however, the extension of this process to water-borne systems, such as emulsion polymerization, is not so trivial. 29 A careful selection of components (monomer, catalyst, growing and dormant species) must be done in order to obtain a successful polymerization 30 In the last decade, some works have described the use of direct and reverse ATRP in ab initio emulsion polymerization, using either conventional or activator generated by electron transfer (AGET) ATRP. 26 The first interval (Interval I) corresponds to the beginning of polymerization, in which particle nucleation takes place.…”

“…The presence of the macroRAFT agents is fundamental for the process not only to control polymerization, but mostly to define the inorganic surface as the polymerization locus and potentially stabilize the hybrid latex particles. Diverse other particles have been successfully encapsulated by the RAFT-mediated emulsion polymerization, including cadmium sulfide 21 and lead sulfide 22 quantum dots, cerium oxide, [23][24][25][26] carbon nanotubes, 27,28 Gibbsite, 29 Montmorillonite clay 30 and even graphene oxide. 31 The encapsulation of anisotropic nano-objects, such as clays, however, is not so trivial.…”

“…However, the encapsulation of anisotropic nano-objects is not so trivial. The disk shape morphology, large aspect ratio and high surface energy of layered minerals difficult the encapsulation process and, while the encapsulation of spherical inorganic particles can be achieved by conventional emulsion or miniemulsion methods, [25][26][27][28] most attempts to encapsulate unmodified 29 and, in some cases, surface-modified 30,31 clay platelets by emulsion polymerization result in the formation of the so-called armored structures. In fact, forming a polymer layer around the platelets implies in imposing a lower energy state to the particles and, to guarantee that the platelets are located and maintained, individually, inside each latex particle, several parameters, related especially to kinetic and/or thermodynamic control mechanisms, must be optimized.…”