scholarly journals Coating of polydopamine on polyurethane open cell foams to design soft structured supports for molecular catalysts

2019 ◽  
Vol 55 (79) ◽  
pp. 11960-11963 ◽  
Author(s):  
Ahmed Ait Khouya ◽  
Miguel L. Mendez Martinez ◽  
Philippe Bertani ◽  
Thierry Romero ◽  
Damien Favier ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Open Cell ◽  
Covalent Grafting ◽  
Open Cell Foams ◽  
Molecular Catalysts

A covalent grafting strategy of molecular catalysts onto a polydopamine-coated flexible three dimensional macroscopic support is presented.

Nonlinear Modeling of 3D Open-Cell Foams

1999 ◽  
Author(s):  
Yu Wang ◽  
Alberto M. Cuitiño
Keyword(s):  
Strain Energy ◽  
Nonlinear Modeling ◽  
Three Dimensional ◽  
Strain Energy Function ◽  
Nonlinear Material ◽  
Open Cell ◽  
Wide Range ◽  
Open Cell Foams ◽  
Explicit Correlation ◽  
Strain Energy Functions

Abstract In this article, we present a hyperelastic model for light and compliant open cell foams with an explicit correlation between microstructure and macroscopic behavior. The model describes a large number of three dimensional structures with regular and irregular cells. The theory is based on the formulation of strain-energy function accounting for stretching which is the main deformation mechanism in this type of materials. Within the same framework, however, bending, shear and twisting energies can also be incorporated. The formulation incorporates nonlinear kinematics which traces the evolution of the structure during loading process and its effects on the constitutive behavior, including the cases where configurational transformations are present leading to non-convex strain-energy functions. Also nonlinear material effects at local or beam level are introduced to accommodate a wide range of different material behaviors. Since the micromechanical formulation presented here has explicit correlation with the foam structure, it preserves in the constitutive relation the symmetries or directional properties of the corresponding structures, including the cases of re-entrant foams which exhibit negative Poisson’s ratio effects. The model captures the central features exhibit by these materials. Predictions of the model for macroscopic uniaxial strain are presented in this article.

Foam Structure: From Soap Froth to Solid Foams

MRS Bulletin ◽  
2003 ◽  
Vol 28 (4) ◽  
pp. 275-278 ◽  
Author(s):  
Andrew M. Kraynik
Keyword(s):  
Three Dimensional ◽  
Edge Length ◽  
Surface Evolver ◽  
Foam Structure ◽  
Open Cell ◽  
Liquid Foams ◽  
Virtual Reconstruction ◽  
Open Cell Foams ◽  
Solid Foams ◽  
Polyhedral Cells

AbstractThe properties of solid foams depend on their structure, which usually evolves in the fluid state as gas bubbles expand to form polyhedral cells. The characteristic feature of foam structure—randomly packed cells of different sizes and shapes—is examined in this article by considering soap froth. This material can be modeled as a network of minimal surfaces that divide space into polyhedral cells. The cell-level geometry of random soap froth is calculated with Brakke's Surface Evolver software. The distribution of cell volumes ranges from monodisperse to highly polydisperse. Topological and geometric properties, such as surface area and edge length, of the entire foam and individual cells, are discussed. The shape of struts in solid foams is related to Plateau borders in liquid foams and calculated for different volume fractions of material. The models of soap froth are used as templates to produce finite element models of open-cell foams. Three-dimensional images of open-cell foams obtained with x-ray microtomography allow virtual reconstruction of skeletal structures that compare well with the Surface Evolver simulations of soap-froth geometry.

scholarly journals A New Methodology to Establish Upper Bounds on Open-Cell Foams Homogenized Properties

10.14311/652 ◽  
2004 ◽  
Vol 44 (5-6) ◽  
Author(s):  
Z. Dimitrovová
Keyword(s):  
Three Dimensional ◽  
Sufficient Conditions ◽  
Upper Bounds ◽  
Geometrical Parameters ◽  
Open Cell ◽  
Linear Elastic ◽  
Internal Forces ◽  
Open Cell Foams ◽  
Necessary And Sufficient ◽  
First Time

The methodology for determining the upper bounds on the homogenized linear elastic properties of cellular solids, described for the two-dimensional case in Dimitrovová and Faria (1999), is extended to three-dimensional open-cell foams. Besides the upper bounds, the methodology provides necessary and sufficient conditions on optimal media. These conditions are written in terms of generalized internal forces and geometrical parameters. In some cases dependence on internal forces can be replaced by geometrical expressions. In such cases, the optimality of some medium under consideration can be verified directly from the microstructure, without any additional calculation. Some of the bounds derived in this paper are published for the first time, along with a proof of their optimality. 

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