Nanoparticle surface properties and relation to particle performance in applications

Fumed silica and carbon black nanoparticles are used in reinforcement, viscosity control, sag resistance, color, etc. in applications such as coatings, adhesives, plastics and elastomers. The performance of particles in those applications is largely determined by the interfacial interaction between particles and polymers. This talk will discuss characterization of surfaces of nanoparticles by gas adsorption technique. Based on gas adsorption measurements we calculate works of adhesion between particles and various liquids and establish compatibility maps with different polymer systems. Examples will be provided on how we are using this knowledge to generate comprehensive materials performance data and innovative product concepts

Nanoparticle surface properties and relation to particle performance in applications

Fumed silica and carbon black nanoparticles are used in reinforcement, viscosity control, sag resistance, color, etc. in applications such as coatings, adhesives, plastics and elastomers. The performance of particles in those applications is largely determined by the interfacial interaction between particles and polymers. This talk will discuss characterization of surfaces of nanoparticles by gas adsorption technique. Based on gas adsorption measurements we calculate works of adhesion between particles and various liquids and establish compatibility maps with different polymer systems. Examples will be provided on how we are using this knowledge to generate comprehensive materials performance data and innovative product concepts

Particle design for the synthesis of tailored polymer nano-composites

The use of submicron-particles to enhance properties of polymeric materials is a widely used practice in many industries, such as, plastics, coatings, adhesives, elastomers, thermosetting composites, etc. From a general frame of reference, the rheological, mechanical, thermal, optical, and electrical performance of particle-polymer composites is governed by two main physical parameters, namely: the state of particle dispersion in the polymer matrix, and the particle-matrix interfacial strength. In this work, the design of Cabot’s submicron-particles along the axes of primary particle size, fractal dimension, and surface chemistry is described in terms of a simple model for particle-polymer and particle-particle interactions based on surface energy measurements. This model allows predictive mapping of particle-polymer systems in phase diagrams that anticipate the state of particle dispersion and interfacial strength for a large range of particle-polymer systems. Several examples are given on the use of this approach in the design of “self-dispersible” or “self-assembling” particles to tailor the rheological, mechanical, thermal, optical, or electrical performance of particle-polymer nano-composites used in coatings, engineering plastics, elastomers, and structural adhesive applications. The design and use of a micro-fluidic device to validate model predictions is also discussed

Oil emulsification using surface-tunable carbon black particles

Emulsification of oil from a subsurface spill and keeping it stable in the water is an important component of the natural remediation process. Motivated by the need to find alternate dispersants for emulsifying oil following a spill, we examine particle-stabilized oil-in-water emulsions. Emulsions that remain stable for months are prepared either by adding acid or salt to carboxyl-terminated carbon black (CB) suspension in water to make the particles partially hydrophobic, adding the oil to this suspension and mixing. When naphthalene, a model potentially toxic polycyclic aromatic hydrocarbon, is added to octane and an emulsion formed, it gets adsorbed significantly by the CB particles, and its transport into the continuous water is markedly reduced. In contrast to an undesirable seawater-in-crude oil emulsion produced using a commercially used dispersant, Corexit 9500A, we demonstrate the formation of a stable crude oil-in-seawater emulsion using the CB particles (with no added acid or salt), important for natural degradation. The large specific surface area of these surface functionalized CB particles, their adsorption capability and their ability to form stable emulsions are an important combination of attributes that potentially make these particles a viable alternative or supplement to conventional dispersants for emulsifying crude oil following a spill. © 2013 American Chemical Society

Swollen Vesicles and Multiple Emulsions from Block Copolymers

ABSTRACT: We engineer novel structures by “stuffing ” the aliphatic regions of self-assembled aggregates with hydrophobic homopolymer. These “stuffed ” vesicles and multiple emulsions are formed in a onestep process when we rehydrate stuffed films made of amphiphilic block copolymer and hydrophobic homopolymer. Without such homopolymer, this system forms micelles. With homopolymer, vesicles form; varying vesicle membrane thicknesses show that these structures incorporate different amounts of homopolymer. Multiple emulsions, containing more homopolymer than stuffed vesicles, are also fabricated using this single-amphiphile system. The system’s incorporation of homopolymer to modify the properties and morphology of the resultant structures is a convenient strategy for preparing self-assembled macromolecular structures with controllable properties

Oil Emulsification Using Surface-Tunable Carbon Black Particles

Emulsification of oil from a subsurface spill and keeping it stable in the water is an important component of the natural remediation process. Motivated by the need to find alternate dispersants for emulsifying oil following a spill, we examine particle-stabilized oil-in-water emulsions. Emulsions that remain stable for months are prepared either by adding acid or salt to carboxyl-terminated carbon black (CB) suspension in water to make the particles partially hydrophobic, adding the oil to this suspension and mixing. When naphthalene, a model potentially toxic polycyclic aromatic hydrocarbon, is added to octane and an emulsion formed, it gets adsorbed significantly by the CB particles, and its transport into the continuous water is markedly reduced. In contrast to an undesirable seawater-in-crude oil emulsion produced using a commercially used dispersant, Corexit 9500A, we demonstrate the formation of a stable crude oil-in-seawater emulsion using the CB particles (with no added acid or salt), important for natural degradation. The large specific surface area of these surface functionalized CB particles, their adsorption capability and their ability to form stable emulsions are an important combination of attributes that potentially make these particles a viable alternative or supplement to conventional dispersants for emulsifying crude oil following a spill. © 2013 American Chemical Society