Mesoporous membranes with complex functional architectures and methods for making

Abstract

In some embodiments, the present invention is directed to methods of making structures with complex functional architectures, where such structures generally comprise at least two mesoporous regions comprising different chemical activity, and where such methods afford spatial control over the placement of such regions of differing chemical activity. In some embodiments, the present invention is also directed to the structures formed by such methods, where such structures are themselves novel.

1 . A structure comprising at least two chemically-distinct mesoporous ceramic regions, wherein at least one such region comprises organic functionality, wherein the regions are in fluid communication with each other, and wherein the regions are further differentiated by at least one property selected from the group consisting of pore morphology, bulk chemical composition, and combinations thereof.  
   
   
       2 . The structure of  claim 1 , wherein the organic functionality emanates from organic-based molecules covalently-integrated into the at least one region comprising such functionality.  
   
   
       3 . The structure of  claim 1 , wherein pore morphology is differentiable between regions if the average pore size of such regions differs by at least about 10 percent.  
   
   
       4 . The structure of  claim 1 , wherein the bulk chemical composition of the mesoporous ceramic regions is selected from the group consisting of SiO 2 , TiO 2 , Al 2 O 3 , ZrO 2 , Y 2 O 3 :ZrO 2 , Y 2 O 3 , and combinations thereof.  
   
   
       5 . The structure of  claim 1 , wherein the organic functionality comprises moieties selected from the group consisting of alkyl, mercapto, carboxyl, vinyl, amine, benzyl, and combinations thereof.  
   
   
       6 . The structure of  claim 5 , wherein the organic functionality further comprises organometallic functionality.  
   
   
       7 . The structure of  claim 1 , wherein the mesoporous ceramic regions comprise pores having an average pore size of between about 1 nm and about 40 nm.  
   
   
       8 . The structure of  claim 7 , wherein the average pore size comprises a standard deviation of between about ±0.1 nm and about ±10 nm.  
   
   
       9 . A structure comprising at least two mesoporous ceramic regions of substantially similar bulk chemical composition and pore morphology, wherein the regions are in fluid communication with each other, wherein at least one such region comprises organic functionality, and wherein at least one such region is substantially devoid of organic functionality.  
   
   
       10 . The structure of  claim 9 , wherein the organic functionality emanates from organic-based molecules covalently-integrated into the at least one region comprising such functionality.  
   
   
       11 . The structure of  claim 10 , wherein the organic functionality comprises moieties selected from the group consisting of alkyl, mercapto, carboxyl, vinyl, amine, benzyl, and combinations thereof.  
   
   
       12 . The structure of  claim 11 , wherein the organic functionality further comprises organometallic functionality.  
   
   
       13 . A structure comprising at least two morphologically-distinct mesoporous ceramic regions, wherein the regions are in fluid communication with each other, and wherein at least one such region comprises organic functionality.  
   
   
       14 . The structure of  claim 13 , wherein the organic functionality emanates from organic-based molecules covalently-integrated into the at least one region comprising such functionality.  
   
   
       15 . The structure of  claim 14 , wherein the organic functionality comprises moieties selected from the group consisting of alkyl, mercapto, carboxyl, vinyl, amine, benzyl, and combinations thereof.  
   
   
       16 . The structure of  claim 15 , wherein the organic functionality further comprises organometallic functionality.  
   
   
       17 . The structure of  claim 13 , wherein the at least two morphologically-distinct mesoporous ceramic regions are deemed morphologically-distinct if the average pore size of such regions differs by at least about 10 percent.  
   
   
       18 . A method comprising the steps of: 
 a) providing a framework in which a mesoporous ceramic can be generated;    b) depositing, in a first region of the framework, a first precursor mixture;    c) treating the first precursor mixture so as to form a region of mesoporous ceramic substructure comprising a first chemical activity;    d) depositing, in a second region of the framework adjacent to the region of mesoporous ceramic substructure comprising a first chemical activity, a second precursor mixture; and    e) treating the second precursor mixture so as to form a region of mesoporous ceramic substructure comprising a second chemical activity, wherein the regions of mesoporous ceramic substructure of first and second chemical activity provide for a mesoporous membrane structure comprising regions of mesoporous ceramic, wherein such regions are differentiable by at least one property selected from the group consisting of chemical activity, pore morphology, bulk chemical composition, and compositions thereof; wherein both of the first and second precursor mixtures comprise a quantity of a self-assembling surfactant species, a quantity of ceramic precursor, and wherein at least one of the first and second precursor mixtures comprises a species for imparting organic-based chemical activity to the region in which it is present.    
   
   
       19 . The method of  claim 18 , wherein the method provides for a mesoporous membrane structure comprising regions of mesoporous ceramic of different chemical activity.  
   
   
       20 . The method of  claim 19 , further comprising a step of depositing additional precursor mixtures into additional regions of the framework, wherein such additional precursor mixtures are treated so as to form additional regions of mesoporous ceramic substructure comprising additional chemical activities, and wherein this additional precursor mixture deposition and treatment provides for a structure comprising at least three chemically-distinct mesoporous ceramic regions.  
   
   
       21 . The method of  claim 19 , wherein the method provides positional control over the deposition of the first and second precursor mixtures and over placement of the regions of mesoporous ceramic substructure so formed.  
   
   
       22 . The method of  claim 19 , further comprising a step of removing at least part of the framework.  
   
   
       23 . The method of  claim 22 , wherein the framework is completely removed to yield mesoporous ceramic nanorods.  
   
   
       24 . The method of  claim 23 , wherein the chemical activity varies within individual nanorods.  
   
   
       25 . The method of  claim 23 , wherein the chemical activity varies between individual nanorods.  
   
   
       26 . The method of  claim 19 , wherein at least one of the first and second chemical activities is at least partially-derived from organic-based molecules covalently-integrated with the region of mesoporous ceramic substructure with which it is associated.  
   
   
       27 . The method of  claim 26 , wherein the organic-based molecules comprise functional moieties selected from the group consisting of alkyl, mercapto, carboxyl, vinyl, amine, benzyl, and combinations thereof.  
   
   
       28 . The method of  claim 27 , further comprising a step of chemically modifying the functional moieties so as to alter the chemical activity of the mesoporous region in which they are present.  
   
   
       29 . The method of  claim 28 , wherein step of chemically modifying involves treating at least some of the functional moieties in the mesoporous regions in which they are present with a species selected from the group consisting of organic species, organometallic species, metallic species, and combinations thereof.  
   
   
       30 . The method of  claim 19 , wherein the regions of mesoporous ceramic substructure comprise a bulk composition selected from the group consisting of SiO 2 , TiO 2 , Al 2 O 3 , ZrO 2 , Y 2 O 3 :ZrO 2 , Y 2 O 3 , and combinations thereof.  
   
   
       31 . A method comprising the steps of: 
 a) depositing, on a substrate, a layer of a first mesoporous ceramic precursor mixture;    b) treating the first precursor mixture so as to form a mesoporous ceramic substructure layer comprising a first chemical activity;    c) depositing, on the mesoporous ceramic substructure layer comprising a first chemical activity, a second precursor mixture; and    d) treating the second precursor mixture so as to form a mesoporous ceramic substructure layer comprising a second chemical activity, wherein the mesoporous ceramic substructure layers of first and second chemical activity collectively provide for a mesoporous membrane structure comprising mesoporous ceramic regions differentiable by at least one property selected from the group consisting of chemical activity, pore morphology, bulk chemical composition, and combinations thereof.    
   
   
       32 . The method of  claim 31 , wherein the method provides for a mesoporous membrane structure of mixed chemical activity.  
   
   
       33 . The method of  claim 32 , further comprising a step of removing the mesoporous ceramic structure of mixed chemical activity from the substrate on which it was formed.  
   
   
       34 . The method of  claim 32 , further comprising a step of forming at least one additional mesoporous ceramic substructure layer within the mesoporous ceramic structure of mixed chemical activity, wherein adjacent layers possess different chemically activity.  
   
   
       35 . The method of  claim 34 , wherein the mesoporous ceramic structure of mixed chemical activity comprises at least three chemically-distinct mesoporous ceramic substructure layers.  
   
   
       36 . The method of  claim 34 , wherein the mesoporous ceramic substructure layer comprising a first chemical activity at least partially derives its chemical activity from organic molecules that are covalently integrated with the mesoporous ceramic substructure layer.  
   
   
       37 . The method of  claim 36 , wherein the organic molecules comprise functional moieties selected from the group consisting of alkyl, mercapto, carboxyl, vinyl, amine, benzyl, and combinations thereof.  
   
   
       38 . The method of  claim 36 , further comprising a step of chemically modifying the organic molecules so as to alter the chemical activity of the mesoporous regions with which they are associated.  
   
   
       39 . The method of  claim 38 , wherein step of chemically modifying involves treating at least some of the organic molecules in the mesoporous regions with which they are associated with a species selected from the group consisting of organic species, organometallic species, metallic species, and combinations thereof.  
   
   
       40 . The method of  claim 32 , wherein the mesoporous ceramic substructure layers comprise a bulk composition selected from the group consisting of SiO 2 , TiO 2 , Al 2 O 3 , ZrO 2 , Y 2 O 3 :ZrO 2 , Y 2 O 3 , and combinations thereof.  
   
   
       41 . The method of  claim 34 , wherein the first and second chemical activities are differentiable and at least partially derived from differences in bulk composition between the substructure layers.