Entropy Penalty-Induced Self-Assembly in Carbon Black or Carbon Fiber Filled Polymer Blends

Abstract

This work attempts to clarify the influence of surface roughness on the thermodynamic interactions between carbon particles and polymer melts. The surface energy of carbon black (CB) and short carbon fibers (VGCF) having different surface roughnesses was estimated by inverse gas chromatography (IGC) and highly sensitive isothermal calorimeter (HS-ITC) measurements using lowmolecular-weight analogues of polymers as probes. We confirmed that the carbon surfaces possess energetic heterogeneity with the most active sites at the graphite crystalline edges, and the interactions in play are van der Waals in nature. Competitive adsorption of two chemically different polymers by incorporation of the carbon particles into the polymer blends was investigated based on SEM and TEM observations. We found that the selective location of CB in the polymer blends does not always depend on the surface tension of polymers but seems to be governed largely by the flexibility of the polymer chains. In VGCFfilled HDPE/PMMA composites, a self-assembled VGCF/HDPE network throughout the PMMA matrix was observed where the flexible HDPE chains are preferentially absorbed at the rough ends of the VGCF filaments. These experimental results lead to the conclusion that surface roughness strongly affects the carbon-polymer interactions, and the entropy penalty may play a main role in competitive adsorption of polymers on the rough carbon surfaces.

Highly energetic compositions based on functionalized carbon nanomaterials

“…It was indicated that the surface roughness of CB and CF strongly affect carbon-polymer interactions and the entropy penalty plays a determining role in the competitive adsorption of polymers on rough carbon surfaces. 44 This may also be the case for energetic polymer binders, such as poly-BAMMO and poly-NIMMO. It has been found that the surface of CB is energetically heterogeneous.…”

Ordered macroporous platinum electrode and enhanced mass transfer in fuel cells using inverse opal structure

“…The formation of self-assembled monolayers of thiols on gold surfaces is well known, but there have only been a few studies reported on the adsorption of organic thiols on carbon. However, carbon black has a surface with energetic heterogeneity, and the most active sites are graphite edges 45,46 . As a consequence, alkanethiols will be adsorbed spontaneously along the edges of a crystal by oxidative addition and reductive elimination of head-thiol groups.…”

Creep Behavior of a Polymer Blend Melt and 3D Observation of the Deformed Bicontinuous Structure by a High-contrast X-ray CT

“…In those composite materials, functional particles are found to localize into one component in each polymer blend (selective localization). [21][22][23] The 3D paths of the bicontinuous structure facilitate the connectivity of functional particles leading to enhancement of, for example, electrical conductivity and/or thermal conductivity.…”