Templating of cylindrical and spherical block copolymer microdomains by layered silicates

Abstract

The influence of a highly anisotropic layered silicate ͑organically modified montmorillonite͒ in directing the mesoscopic self-assembly of a block copolymer blend is studied as a model for the development and tailoring of templated inorganic-organic hybrid materials. The potential for nanometer thick layers to induce large-scale mesoscopic ordering of cylindrical and spherical microdomains in asymmetric block copolymers is studied using a combination of rheology, electron microscopy, and small angle neutron scattering. Spherical microdomains arranged on a bcc lattice are templated by the anisotropic layered silicate and the kinetics of their growth are dramatically accelerated by the presence of even 0.1 wt.% ͑0.04 vol.%͒ of the filler. However, for cylindrical microdomain ordering, the kinetics are essentially unaffected by the addition of layered silicates and the development of three-dimensional mesoscopic order is possibly even disrupted. These results suggest that for the development of three-dimensional well-ordered nanostructures, the surface defining the pattern has to be significantly larger than the leading dimension of the structure being templated.

Morphological evolution of block copolymer nanocomposites submitted to extensional flows

“…The results corroborate the works previously reported [25,26] who studied the state of clay dispersion in triblock copolymers. Clay particle surfaces were shown to have higher interaction with the PS chains, which exhibit a mild polarity, necessary to promote the intercalation into the clay galleries, which are also slightly polar, despite the presence of the double-tailed apolar ammonium cations [38].…”

“…In particular, the morphology of block copolymers can be controlled by subjecting them to shear or extensional flows. Moreover, the addition of nanoparticles can induce morphological changes on a block copolymer, depending on the chemical affinity between the nanoparticles and the different domains present in the copolymer [23][24][25][26].…”

Rheological properties of asphalt/SBS/clay blends

“…Lee et al showed that an organically modified montmorillonite leads to a change in the microphase separation behaviour of styrene-(ethylene-co-butylene)-styrene triblock copolymers (SEBS), thus also influencing the order-disorder transitions [28]. Analogously, the influence of the addition of small quantities of anisotropic layered silicates on the ordering of block copolymers was studied by Krishnamoorti et al [29] and Silva et al [30][31][32]. The effect of the preparation technique was investigated by Yamaguchi and Yamada [33], Chang et al [34], Carastan and Demarquette [35].…”

Ordering Behavior of Layered Silicate Nanocomposites with a Cylindrical Triblock Copolymer

“…Recently, the organosilicate layer nanocomposites have been prepared with multicomponent polymeric systems such as polymer blends and block copolymers. [17][18][19][20][21] Block copolymers have received much scientific and technological attention because of their ability to Summary: The ordering behavior of the nanocomposites of organically modified montmorillonite (OMMT) with a cylindrical triblock copolymer of polystyrene-block-poly-(ethylene-co-butylene)-block-polystyrene (SEBS) has been investigated by temperature-resolved small-angle X-ray scattering (SAXS) and rheometry. X-Ray diffraction (XRD) confirms that the polymer chains are successfully intercalated with the interlayer gallery of the silicates.…”

“…[28 -38] The layered organosilicate nanocomposites have been also prepared with diblock and triblock copolymers. [17][18][19][20] Ren et al reported the stress relaxation behavior of layered organosilicate nanocomposites with a diblock copolymer of polystyrene-block-polyisoprene (PS-b-PI) with a spherical morphology. [20] The linear dynamic oscillatory moduli and the stress relaxation moduli suggest that at short times the relaxation of the nanocomposites is essentially unaffected by the presence of the layered organosilicates, whereas, at long times, the hybrids with the organosilicate loadings in excess of 6.7 wt.-% exhibit pseudo-solid-like behavior.…”