Methods for creating a surface energy gradient

Abstract

A method of derivatizing a fluid-impervious surface with a mixed monolayer to create a surface energy gradient comprising the steps of a) Exposing a base surface to a first solution comprising a plurality of molecules of the formula X1-J1-M1 wherein X1 and M1 represent separate functional groups and J1 represents a spacer moiety that, together, are able to promote formation from solution of a self-assembled monolayer for sufficient time to form a monolayer surface having a substantially uniform surface energy on the base surface. b) Removing a portion of the monolayer formed in (a) such that a portion of the base surface is again fully or partially exposed. c) Exposing the portion of the base surface from (b) to a second solution comprising a plurality of molecules of the formula X2-J2-M2 wherein the functional group M2 has a different surface energy from that of the functional group M1 such that a surface energy gradient is formed.

1 ) A method of derivatizing a fluid-impervious surface with a mixed monolayer to create a surface energy gradient from a proximal location to a distal location within at least one distinct region of length L and width W wherein L equals the distance from the proximal location to the distal location, W is 20 nanometers or greater, and the ratio of L/W is greater than 2 and wherein any portions of the surface that border the at least one distinct region along the dimension L have substantially equal surface energies comprising the steps of
 a) Exposing a base surface to a first solution comprising a plurality of molecules of the formula X1-J1-M1 wherein X1 and M1 represent separate functional groups and J1 represents a spacer moiety that, together, are able to promote formation from solution of a self-assembled monolayer for sufficient time to form a monolayer surface having a substantially uniform surface energy on the base surface.   b) Removing a portion of the monolayer formed in (a) such that a portion of the base surface of length L and width W is again fully or partially exposed.   c) Exposing the portion of the base surface from (b) to a second solution comprising a plurality of molecules of the formula X2-J2-M2 and a plurality of molecules of the formula X1-J1-M1 wherein the functional group M2 has a different surface energy from that of the functional group M1 such that a surface energy gradient is formed in the at least one distinct region of length L and width W.   
     
     
         2 ) The method of  claim 1 , wherein removing a portion of the monolayer is done while the base surface and monolayer surface from (a) are immersed in the first solution or the second solution. 
     
     
         3 ) The method of  claim 1  wherein removal of a portion of the monolayer of (a) is performed using a method or combination of methods selected from the group consisting of passing an instrument along the monolayer surface created in (a) with sufficient force to remove a portion of the monolayer created in (a), etching chemically the portion to be removed, etching physically the portion to be removed, cutting with a laser, cutting with water, drilling, sonic means, etching through thermometric exposure, blasting with grit, and cutting with an instrument. 
     
     
         4 ) The method of  claim 2 , wherein removal of the portion of the monolayer of (a) is performed while at the same time increasing amounts of a third solution comprising a molecule of the formula X2-J2-M2 so that a mixed monolayer surface of M1 and M2 moieties is formed with a molar ratio of M2 to M1 that increases along the length L. 
     
     
         5 ) The method of  claim 1 , wherein the X2 and J2 groups of the second solution are the same chemical composition as the X1 and J1 groups of the first solution. 
     
     
         6 ) The method of  claim 4 , wherein the X2 and J2 groups of the third solution are the same chemical composition as the X1 and J1 groups of the first solution. 
     
     
         7 ) The method of  claim 4 , wherein the third solution has a solvent different from that of the first solution or the second solution. 
     
     
         8 ) The method of  claim 1  wherein steps (b) and (c) are performed in the same solutions of the same solvent. 
     
     
         9 ) The method of  claim 1  wherein the monolayer is removed by an atomic force microscopy probe or a scanning probe lithography probe. 
     
     
         10 ) The method of  claim 1  wherein the gradient is created on the surface of a group consisting of the inside of a tube, the outside of a tube, within a channel, on a medical stent, an analytical slide and any combination thereof. 
     
     
         11 ) The method of  claim 1  wherein the base surface is a metal oxide comprising a metal oxide from the group comprising silica, alumina, quartz, glass, or the like. 
     
     
         12 ) The method of  claim 1  wherein the base surface is a metal selected from the group consisting of gold, silver, copper, nickel, aluminum, cadmium, zinc, palladium, platinum, mercury, lead, iron, chromium, manganese, tungsten, or any combination thereof. 
     
     
         13 ) The method of  claim 12  wherein the functional group X comprises at least one sulfur-containing functional group selected from the group consisting of thiols, sulfides, disulfides, or any combination thereof. 
     
     
         14 ) The method of  claim 1  wherein the base surface is doped or undoped silicon. 
     
     
         15 ) The method of  claim 14  wherein the functional group X is selected from the group consisting of silanes or chlorosilanes. 
     
     
         16 ) The method of  claim 1  wherein the base surface is selected from the group comprising epoxy compounds, polysulfone compounds, plastics, polyanhidrides, polylactic acids, polyglycolic acids, other polymers, or any combination thereof. 
     
     
         17 ) The method of  claim 1  wherein the base surface comprises a metalized film. 
     
     
         18 ) The method of  claim 17  wherein the metal comprising the film is selected from the group consisting of gold, silver, copper, nickel, aluminum, cadmium, zinc, palladium, platinum, mercury, lead, iron, chromium, manganese, tungsten, or any combination thereof. 
     
     
         19 ) The method of  claim 1  wherein the functional groups M1 and M2 are selected from the group consisting of ionic, nonionic, polar, nonpolar, halogenated, alkyl, aryl or other functionalities, —OH, —CONHR, —CONHCOR, —NHR, —COOH, —COOR, —CSNHR, —COR, —RCSR, —RSR, —ROR, —SOOR, —RSOR, —CONR2, —(OCH2CH2)nOH, —(OCH2CH2)nOR—CH3, —NR2, —CN, —(CF2)nCF3, —CO2CH3, —CONHCH3, —CR, CHCH2, —OCH2CF2CF3, Cl, Br, olefins, and the like, and any combination thereof, wherein n is 1-20 and R is hydrogen or an organic group such as a hydrocarbon or fluorinated hydrocarbon including alkyl, alkenyl, alkynyl, cycloalkyl, aryl, alkaryl, aralkyl, and the like. 
     
     
         20 ) The method of  claim 3  wherein two or more distinct regions having a surface energy gradient are created by using an instrument with 2 or more tips.