Kinetically Trapped Co-continuous Polymer Morphologies through Intraphase Gelation of Nanoparticles

Abstract

We describe an approach to prepare co-continuous microstructured blends of polymers and nanoparticles by formation of a percolating network of particles within one phase of a polymer mixture undergoing spinodal decomposition. Nanorods or nanospheres of CdSe were added to near-critical blends of polystyrene and poly(vinyl methyl ether) quenched to above their lower critical solution temperature. Beyond a critical loading of nanoparticles, phase separation is arrested due to the aggregation of particles into a network (or colloidal gel) within the poly(vinyl methyl ether) phase, yielding a co-continuous spinodal-like structure with a characteristic length scale of several micrometers. The critical concentration of nanorods to achieve kinetic arrest is found to be smaller than for nanospheres, which is in qualitative agreement with the expected dependence of the nanoparticle percolation threshold on aspect ratio. Compared to structural arrest by interfacial jamming, our approach avoids the necessity for neutral wetting of particles by the two phases, providing a general pathway to co-continuous micro- and nanoscopic structures.

Preparation of polyethylene microporous membranes with high water permeability from thermally induced multiple phase transitions

“…Ma et al [26] found that adding nanoparticle (MMT and PTFE (Polytetrafluoroethylene)) in PVDF/ DPK (diphenyl ketone) system decreased the pore size of membrane, which could be attributed to the short time for the SLPS owing to the fast crystallization in presence of nanoparticle. Li et al [27] even found that the CdSe nanorods and nanospheres kinetically arrested co-continuous morphologies in demixing polymer blends due to gelation of the nanoparticles within one of the polymer phases. Besides these isotropic or inert additives, self-assembly (or sol-gel transition) has also been adopted recently to form nano-objects in-situ in polymer/diluent system during TIPS.…”

Using Janus Nanoparticles To Trap Polymer Blend Morphologies during Solvent-Evaporation-Induced Demixing

“…17,18 Li et al demonstrated similar results in a system where the particles were poorly dispersed and not interfacially active, leading to a gel of CdSe−TOPO nanoparticles within the PVME domain of a PS/PVME blend undergoing spinodal decomposition, kinetically arresting the bicontinuous structure. 19 These reports extended the concept of "bijels" 20−22 (bicontinuous, kinetically stabilized emulsion gels), formed by the jamming of neutrally wetting particles at the interface of low molecular weight fluids during demixing, to polymeric systems.…”

Structure, viscoelasticity, and interfacial dynamics of a model polymeric bicontinuous microemulsion

“…[1][2][3][4][5][6][7] To date, a host of ingredients (metals, 8 oxides, 9,10 surfactants, 6 and polymers 3 ) and processing strategies (both kinetic 11,12 and thermodynamic 3,6 ) have been exploited to control the characteristic length scale and physical properties of such co-continuous structures. [1][2][3][4][5][6][7] To date, a host of ingredients (metals, 8 oxides, 9,10 surfactants, 6 and polymers 3 ) and processing strategies (both kinetic 11,12 and thermodynamic 3,6 ) have been exploited to control the characteristic length scale and physical properties of such co-continuous structures.…”