Facile synthesis and biomimetic amine-functionalization of chitosan foam for CO capture.

A high-performance biomass-based adsorption materials could be the promising trend for CO capture and storage technology. However, the direct application of biomass-based porous materials as a CO adsorbent with enhanced performance is an emerging issue. Herein, a facile synthesis and a biomimetic strategy were combined to prepare amine-functionalized chitosan foam for CO capture, and then a porous biomass is achieved for the application on the environment protection field.

Construction of Oxygen-Rich Carbon Foams for Rapid Carbon Dioxide Capture.

As carbon dioxide (CO) adsorbents, porous materials with high specific surface areas and abundant CO-philic groups always exhibit high CO capacities. Based on this consensus, a category of oxygen-rich macroporous carbon foams was fabricated from macroporous resorcinol-formaldehyde resins (PRFs), which were obtained via an oil-in-water concentrated emulsion. By the active effect of potassium hydroxide (KOH) at high temperatures, the resultant carbon foams (ACRFs) possessed abundant micropores with rich oxygen content simultaneously.

Anisotropic Dynamics of Binary Particles in Confined Geometries.

The diffusion dynamics of colloidal particles in a good solvent confined between two parallel quartz walls have been studied within the framework of dynamical density functional theory. The highly ordered density layers induced by interfacial effects give rise to the oscillating dynamics, resulting in position-dependent structural relaxations and diffusivities. Further investigation reveals that particle size, particle-wall interaction, and slitpore width play different roles in affecting the oscillating behaviors along different directions.

Fabrication and characterization of antistatic epoxy composite with multi-walled carbon nanotube-functionalized melamine foam.

A novel strategy for synthesizing an antistatic epoxy composite was carried out. Pre-embedded antistatic melamine foam was first synthesized and then used to prepare an antistatic epoxy composite. Azidized polyacrylic acid (APAA) was grafted onto multiwalled carbon nanotubes (APAA-MWCNTs) by direct functional modification of the MWCNT sidewalls.

The mechanism of roughness-induced CO microbubble nucleation in polypropylene foaming.

Within the framework of classical density functional theory, the thermodynamic driving forces for CO microbubble nucleation have been quantitatively evaluated in the foaming of polypropylene containing amorphous and crystalline structures. After the addition of fluorinated polyhedral oligomeric silsesquioxane particles into the polypropylene matrix, we construct different composite surfaces with nanoscale roughness for bubble nucleation. Meanwhile, as the dissolved CO molecules increase, the corresponding CO/PP binary melts can be formulated in the systems.

Diffusive dynamics of polymer chains in an array of nanoposts.

We present a dynamic density functional approach to study polymer chain diffusion in a good solvent in the confinement of a nanopost array. Three key results emerge from our study. First, we show different scaling laws of the chains moving toward, close to, and around the posts.

Control of Uniform and Interconnected Macroporous Structure in PolyHIPE for Enhanced CO2 Adsorption/Desorption Kinetics.

The highly uniform and interconnected macroporous polymer materials were prepared within the high internal phase hydrosol-in-oil emulsions (HIPEs). Impregnated with polyethylenimine (PEI), the polyHIPEs were then employed as solid adsorbents for CO2 capture. Thermodynamic and kinetic capture-and-release tests were performed with pure CO2, 10% CO2/N2, and moist CO2, respectively.

Understanding Controls on Wetting at Fluorinated Polyhedral Oligomeric Silsesquioxane/Polymer Surfaces.

Fluorinated polyhedral oligomeric silsesquioxane (F-POSS) nanoparticles have been widely used to enhance the hydrophobicity or oleophobicity of polymer films via constructing the specific micro/nanoscale roughness. In this work, we study the oleophobicity of pure and F-POSS-decorated poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) films using a dynamic density functional theory approach. The role of nanoparticle size and coverage and the chemical features of F-POSS and the polymer film in the wetting behavior of diiodomethane droplets has been integrated to the remaining ratio of surface potential to quantitatively characterize the corner effect.

Understanding the microstructure of particle dispersion in confined copolymer nanocomposites.

The microstructures of diblock copolymer/particle composites confined in slitpores have been investigated using a density functional theory approach. It has been shown that, under the condition of confinement, particles display different distributions near the solid surfaces, in the microdomains of two blocks, and at the microphase interfaces. The final dispersion depends on the balance between the enthalpic contribution arising from the particle-segment attraction as well as the entropy-driven depletion attraction induced by the polymer conformation and the confinement environment.

Effect of chain topology of polyethylenimine on physisorption and chemisorption of carbon dioxide.

Polyethylenimine (PEI) is a promising candidate for CO2 capture. In this work, the physisorption and chemisorption of CO2 on various low-molecular-weight PEIs are investigated to identify the effect of chain architecture on sorption. The reliability of theoretical calculations are partially supported by our experimental measurements.

β-Cyclodextrin functionalized polystyrene porous monoliths for separating phenol from wastewater.

A β-cyclodextrin (β-CD) functionalized polystyrene porous monolith was prepared by the following procedure: First, β-CD was modified with allyl bromide leading to allyl-β-cyclodextrin (allyl-β-CD); then a concentrated emulsion was prepared using a mixture of allyl-β-CD, styrene, and divinyl benzene as the continuous phase and water as the dispersed phase. In the third step, a β-cyclodextrin (β-CD) functionalized polystyrene porous monolith was obtained by copolymerization of allyl-β-CD and styrene followed by removal of the water phase. Since the allyl-β-CD contained both hydrophilic and hydrophobic groups, it tended to move towards the water/oil interface.

Evaluation of macroscale wetting equations on a microrough surface.

The wettability of critical droplets on microscale geometric rough surfaces has been investigated using a density functional theory approach. In order to analyze the effect of roughness on nucleation free-energy barriers, the local density fluctuations at liquid-solid interfaces induced by the multi-interactions of a corner substrate are presented to interpret the interfacial free-energy variations, and the vapor-liquid-solid contact line tensions are derived from the contact angles of nuclei to account for the three-phase contact energies. The corresponding wetting diagrams have been constructed in Cassie, Wenzel, and impregnation regions.

Fabrication of interfacial functionalized porous polymer monolith and its adsorption properties of copper ions.

The interfacial functionalized poly (glycidyl methacrylate) (PGMA) porous monolith was fabricated and applied as a novel porous adsorbent for copper ions (Cu(2+)). PGMA porous material with highly interconnected pore network was prepared by concentrated emulsion polymerization template. Then polyacrylic acid (PAA) was grafted onto the interface of the porous monolith by the reaction between the epoxy group on PGMA and a carboxyl group on PAA.

Carbon dioxide adsorbent based on rich amines loaded nano-silica.

An easy strategy to obtain an effective carbon dioxide adsorbent based on rich amines functionalized nano-silica was proposed. Polyacrylic acid (PAA), acted as a multi-functional bridge, was firstly immobilized onto the surface of silica nanoparticles. Each carboxylic acid group was subsequently reacted with an amine group of alkylamines, and plenty of remained amines groups could be coated onto silica nanoparticles.

Modified PRISM theory for confined polymers.

We propose a modified polymer reference interaction site model (PRISM) to describe the interfacial density profiles of polymers in contact with planar and curved solid surfaces. In the theoretical approach, a bridge function derived from density functional method is included. In description of hard-sphere polymer at planar and curved surfaces with an arbitrary external field, the effect of modification has been validated by the available simulation data, except for low density system.

Structures and surface tensions of fluids near solid surfaces: an integral equation theory study.

In this work, integral equation theory is extended to describe the structures and surface tensions of confined fluids. To improve the accuracy of the equation, a bridge function based on the fundamental measure theory is introduced. The density profiles of the confined Lennard-Jones fluids and water are calculated, which are in good agreement with simulation data.

A theoretical study of structure-solubility correlations of carbon dioxide in polymers containing ether and carbonyl groups.

This work involves a theoretical study to investigate the effects of the structure on CO(2) sorption in polymers, where poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), poly(vinyl acetate) (PVAc), poly(ethylene carbonate) (PEC) and poly(propylene carbonate) (PPC) were examined. In the theoretical approach, the multi-site semiflexible chain model and the renormalized technique of electrostatic potentials were incorporated into the polymer reference interaction site model (PRISM). To test the theory, molecular dynamic simulations were performed using the TraPPE-UA force field.

Interconnected porous epoxy monoliths prepared by concentrated emulsion templating.

Porous epoxy monoliths were prepared via a step polymerization in a concentrated emulsion stabilized by non-ionic emulsifiers and colloidal silica. A solution in 4-methyl-2-pentanon was used as the continuous phase, which contained glycidyl amino epoxy monomer (GAE), curing agent, and an emulsifier. An aqueous suspension of colloidal silica was used as the dispersed phase of the concentrated emulsion.

Formation of porous epoxy monolith via concentrated emulsion polymerization.

Step polymerization was introduced into the concentrated emulsion templating method and was illustrated with the preparation of porous epoxy monolith. A solution of diglycidyl ether of bisphenol-A (DGEBA), its curing agent low molecular weight polyamide resin, and surfactant nonyl phenol polyoxyethylene ether in 4-methyl-2-pentanon as a solvent was used as the continuous phase, an aqueous suspension of colloidal silica as the dispersed phase of the concentrated emulsion. After the continuous phase polymerized and the dispersed phase removed, a porous material is obtained.

Preparation of hydrophilic/hydrophobic porous materials.

A novel porous material was designed and prepared in this work. A hydrophobic open-celled porous polystyrene (PS) was first synthesized via a concentrated emulsion polymerization of water in styrene. Subsequently the porous polystyrene was saturated with an aqueous solution of acrylamide (AM) and an initiator, which was subjected to another polymerization and the resulted polyacrylamide (PAM) penetrated in the cells and intercellular pores of the PS matrix.