Assembly of free-standing films using a layer-by-layer process

Abstract

A method for the layer-by-layer assembly of a free standing thin film includes the steps of preparing a support with a suitable substrate; forming a thin film having a plurality of layers onto the substrate utilizing a layer-by-layer assembly process; removing the substrate and thin film from the support; and separating the substrate from the thin film. Various compounds improving the strength, flexibility, tension and other mechanical properties may be included in the assembly to improve the structural quality of the film. Similar effect may also be achieved by cross-linking the applied layers.

1 - 8 . (canceled)  
     
     
         9 . A free-standing stratified composite polymeric membrane comprising: 
 a first layer having a first high molecular weight material;    a second layer adjacent to said first layer, said second layer having a second high molecular weight material;    wherein each of said layers have a thickness less than 100 nm; and    wherein said high molecular weight materials have an affinity for each other.    
     
     
         10 . The membrane of  claim 9  further comprising additional layers wherein said additional layers alternately comprise said first high molecular weight material and said second high molecular weight material.  
     
     
         11 . The membrane of  claim 9  wherein said high molecular weight materials are chosen from the group consisting of polyelectrolytes, proteins, nanoparticles, nanowires, nanotubes, exfoliated clays, dyes, vesicles, viruses, DNAs, RNAs, oligonucleotides, organic and inorganic colloids.  
     
     
         12 . The membrane of  claim 9  wherein said affinity between said first high molecular weight material and said second high molecular weight material is electrostatic attraction.  
     
     
         13 . The membrane of  claim 9  wherein said affinity between said first high molecular weight material and said second high molecular weight material is van der Waals forces, hydrogen forces, or electron exchange.  
     
     
         14 . The membrane of  claim 9  wherein said first high molecular weight material and said second high molecular weight material are chemically cross-linked.  
     
     
         15 . The membrane of  claim 9  wherein at least one of said first high molecular weight material and said second high molecular weight material is a biological compound that retains its biological activity.  
     
     
         16 . The membrane of  claim 9  further comprising a third layer having a third high molecular weight material.  
     
     
         17 . The membrane of  claim 10  further comprising additional layers having additional high molecular weight materials.