Surface modification of a porous polymer monolith and products therefrom

Abstract

A process is provided for modifying a porous polystyrene monolith to render its internal pore surfaces grafted with alkyl groups, preferably of at least four carbon atoms, which includes the step of alkylating the monolith with a uniform liquid solution containing a Friedel-Crafts catalyst and an alkyl halide. A surface-modified monolith produced thereby is an efficient separation medium in reversed-phase liquid chromatography for both small and large biomolecules.

What is claimed:  
     
         1 . A process for the surface modification of a porous polystyrenic monolith, comprising the steps of: 
 (a) wetting the monolith internal through-pore surfaces with an organic solvent used in step (b);    (b) treating the internal through-pore surfaces of said monolith by contacting said monolith pores with a uniform liquid solution comprising a Friedel-Crafts catalyst, an alkyl halide, and an organic solvent so as to alkylate the internal through-pore surfaces; and    (c) removing the post-reaction solution from the alkylated through-pore surfaces by rinsing the organic solvent used in step (b) through said monolith.    
     
     
         2 . The process of  claim 1 , further comprising washing said alkylated through-pore surfaces by sequentially rinsing a series of solvents through said monolith.  
     
     
         3 . The process of  claim 1 , wherein said treating of the internal through-pore surfaces is performed with heating.  
     
     
         4 . The process of  claim 1 , wherein said wetting of the monolith internal through-pore surfaces comprises rinsing said organic solvent through said monolith.  
     
     
         5 . The process of  claim 1 , wherein said contacting of said monolith through-pores with a uniform liquid solution comprises filling said monolith with said uniform liquid solution and then rinsing said uniform liquid solution through said monolith.  
     
     
         6 . The process of  claim 1 , wherein said porous monolith comprises a cross-linked polystyrene-based copolymer.  
     
     
         7 . The process of  claim 1 , wherein said porous monolith comprises poly(styrene-co-divinylbenzene).  
     
     
         8 . The process of  claim 1 , further comprising preparing said porous polystyrenic monolith in situ in a tube prior to said alkylation.  
     
     
         9 . The process of  claim 1 , wherein said monolith is contained in a tube.  
     
     
         10 . The process of  claim 9 , wherein said tube comprises a metal tube, plastic tube, or capillary tube.  
     
     
         11 . The process of  claim 1 , wherein said tube comprises a microchip made from silicon, plastic, or glass.  
     
     
         12 . The process of  claim 1 , wherein said monolith is a molded in a fused silica capillary.  
     
     
         13 . The process of  claim 1 , wherein said monolith is contained within a rigid micro-opening of a silicon or polymer chip comprising a microfluidic separation device.  
     
     
         14 . The process of  claim 1 , wherein said Friedel-Crafts catalyst is aluminum chloride (AlCl 3 ), aluminum bromide (AlBr 3 ), or antimony pentachloride (SbCl 5 ).  
     
     
         15 . The process of  claim 1 , wherein said alkyl halide is a primary, secondary, or tertiary chloride or bromide having at least four carbon atoms.  
     
     
         16 . The process of  claim 1 , wherein said alkyl halide has 4, 8, or 18 carbon atoms.  
     
     
         17 . The process of  claim 1 , wherein said alkyl halide is linear, branched, cyclic, or combination thereof.  
     
     
         18 . The process of  claim 1 , wherein said alkyl halide is octadecyl chloride.  
     
     
         19 . The process of  claim 1 , wherein said solvent is nitrobenzene (C 6 H 5 NO 2 ) or nitromethane (CH 3 NO 2 ), or mixture thereof.  
     
     
         20 . The process of  claim 1 , wherein said solvent is capable of dissolving said Friedel-Crafts catalyst and is miscible in said alkyl halide.  
     
     
         21 . The process of  claim 2 , wherein said series of solvents are N,N-dimethylformamide, 1 M HCl aqueous solution, water, and acetonitrile, respectively.  
     
     
         22 . The process of  claim 1 , wherein said wetting and rinsing are performed under pressure.  
     
     
         23 . The product produced by the process of  claim 1 .  
     
     
         24 . A porous polystyrenic monolith comprising alkylated internal through-pore surfaces.  
     
     
         25 . The product of  claim 24 , wherein said porous monolith comprises a chromatography media.  
     
     
         26 . The product of  claim 24 , wherein said porous monolith is a cross-linked polystyrene-based copolymer.  
     
     
         27 . The product of  claim 24 , wherein said porous monolith comprises poly(styrene-co-divinylbenzene).  
     
     
         28 . The product of  claim 24 , wherein said porous monolith is in situ prepared in a tube.  
     
     
         29 . The product of  claim 24 , wherein said monolith is contained in a tube.  
     
     
         30 . The product of  claim 29 , wherein said tube comprises a metal tube, plastic tube, or capillary tube.  
     
     
         31 . The product of  claim 29 , wherein said tube comprises a microchip made from silicon, plastic, or glass.  
     
     
         32 . The product of  claim 24 , wherein said monolith is a molded in a fused silica capillary.  
     
     
         33 . The product of  claim 24 , wherein said monolith is contained within a rigid micro-opening of a silicon or polymer chip comprising a microfluidic separation device.  
     
     
         34 . The product of  claim 24 , wherein said alkylated pore surfaces comprise alkyl groups having at least four carbon atoms.  
     
     
         35 . The product of  claim 34 , wherein said alkyl group has 4, 8, or 18 carbon atoms.  
     
     
         36 . The product of  claim 34 , wherein said alkyl group is linear, branched, cyclic, or combination thereof.  
     
     
         37 . The product of  claim 34 , wherein said alkyl group is octadecyl.