title: A nanotechnology pathway to arresting phase separation in soft nanocomposites.
abstract: Direct observation of the miscibility improving effect of ultra-small polymeric nanoparticles (radius ≈4 nm) in model systems of soft nanocomposites is reported. We have found thermodynamically arrested phase separation in classical poly(styrene) (PS)/poly(vinyl methyl ether) blends when PS linear chains were totally replaced by ultra-small, single chain PS nanoparticles, as determined by thermo-optical microscopy measurements. Partial arrested phase splitting on heating was observed when only some of the PS chains were replaced by unimolecular PS nanoparticles, leading to a significant increase of the lower critical solution temperature (LCST) of the system (up to 40 °C at 15 vol.-% nanoparticle content). Atomic force microscopy and rheological experiments supported these findings. Thermodynamic arrest of the phase separation process induced by replacement of linear polymer chains by unimolecular polymer nanoparticles could have significant implications for industrial applications requiring soft nanocomposite materials with excellent nanoparticle dispersion in a broad temperature range.
authors: Centro de Física de Materiales (CSIC, UPV/EHU)-Materials Physics Center, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain. josetxo_pomposo@ehu.es
authors: José A
authors: JA
authors: Pomposo
authors: Alaitz Ruiz
authors: AR
authors: de Luzuriaga
authors: Iñaki
authors: I
authors: García
authors: Agustín
authors: A
authors: Etxeberria
authors: Juan
authors: J
authors: Colmenero
mesh_terms: D008738:Methyl Ethers / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D053761:Nanocomposites / Q000737:chemistry*; D036103:Nanotechnology; D011137:Polystyrenes / Q000737:chemistry*; D011145:Polyvinyls / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D008738:Methyl Ethers; D011137:Polystyrenes; D011145:Polyvinyls; C510739:poly(vinyl methyl ether)