Composite Material

Abstract

Disclosed herein are engineered composite materials suitable for applications that can benefit from a composite material capable of interacting with or responding to, in a controlled or predetermined manner, changes in its surrounding environment. The composite material is generally includes a gradient layer structure of a sequence of at, e.g., three or more gradient-contributing layers of microscale particles, wherein a mean particle size of particles of neighboring gradient-contributing layers in the cross section of the gradient layer structure varies from layer to layer, thereby forming a particle size gradient, and in contact with the gradient layer structure, a densely packed particle structure including densely packed microscale particles, wherein a mean particle size of the densely packed microscale particles does not form a particle size gradient in the cross section of the densely packed particle structure.

1 . A method of making a multilayer composite material for attenuating a compression wave, comprising the actions of:
 a. depositing a first plurality of sub-macroscale particles having a first mean diameter and suspended in a first liquid medium onto a substrate;   b. subjecting the first plurality and the substrate to a first environment for a first preselected amount of time sufficient to cause the first liquid medium to evaporate leaving a first layer structure of the plurality of sub-macroscale particles on the substrate;   c. depositing a second plurality of sub-macroscale particles having a second mean diameter, different from the first mean diameter, and suspended in a second liquid medium onto first layer structure; and   d. subjecting the second plurality, the first plurality and the substrate to a second environment for a second preselected amount of time sufficient to cause the second liquid medium to evaporate leaving a second layer structure of the plurality of sub-macroscale particles on the first layer structure,
 wherein the first plurality of sub-macroscale particles and the second plurality of sub-macroscale particles are selected so that the first layer structure and the second layer structure form an interface therebetween that causes a deflection of the compression wave upon crossing the interface from the first layer structure to the second layer structure. 
   
     
     
         2 . The method of  claim 1 , further comprising the action of irradiating the substrate so as to create an organic acid functionality on a surface of the substrate, thereby increasing adhesion of the sub-macroscale particles thereto. 
     
     
         3 . The method of  claim 1 , wherein the sub-macroscale particles comprise particles selected from a group consisting of: polystyrene, silica and carbon. 
     
     
         4 . The method of  claim 1 , wherein the sub-macroscale particles comprise particles selected from a group consisting of: solid, hollow and liquid filled. 
     
     
         5 . The method of  claim 1 , further comprising the action of functionalizing the sub-macroscale particles prior to deposition. 
     
     
         6 . The method of  claim 5 , wherein the functionalizing action comprises providing the sub-macroscale particles so at to include carboxylic acid functionality. 
     
     
         7 . The method of  claim 5 , wherein the functionalizing action comprises polarizing the sub-macroscale particles. 
     
     
         8 . The method of  claim 5 , wherein the sub-macroscale particles comprise particles selected from a group consisting of: nanoscale particles, microscale particles and combinations thereof.