Formation of Grafted Macromolecular Assemblies with a Gradual Variation of Molecular Weight on Solid Substrates

Abstract

The development of new polymeric materials and structures relies primarily on controlled polymerizations, chain growth polymerizations that proceed without irreversible chain transfer, and chain termination. Recent advances in living radical polymerizations have led to the advancement of robust and simple polymerization methodologies. In particular, atom transfer radical polymerization (ATRP), pioneered by Sawamoto 1 and Matyjaszewski, 2 provides a convenient means of synthesizing end-functionalized and body-functionalized polymers, thereby enabling the synthesis of a variety of polymer architectures, including block copolymers, multiarmed stars, hyperbranched polymers, and polymer combs with well-defined composition and relatively low molecular weight polydispersities. 3 Many types of monomers including acrylates, methacrylates, styrenes, vinylpyridines, acrylonitrile, and acrylamides have been polymerized successfully via ATRP.Continuous molecular gradients represent chief tools for combinatorial chemistry and materials science. 4,5 These multivariant methods enable systematic variation of one or more physicochemical properties, thus enabling systematic exploration of the broad parameter space, improved efficiency, and lower cost. 6 Surface-tethered polymer structures represent an effective means of tuning the physicochemical properties of substrates. Recently, techniques, involving the patterning of polymer layers grafted to the substrate, have been developed

Poly(l-lysine)-grafted-poly(ethylene glycol)-based surface-chemical gradients. Preparation, characterization, and first applications

“…these mechanisms. 43 A variety of techniques to generate grafted polymer gradients is available, including the preparation of initiator gradients by corona discharge, 44,45 by vapor diffusion, 46,47 by controlling adsorption kinetics 48 or temperature, 49 the control of the polymerization conditions, e.g., time 50,51 or temperature, 52 and diffusion methods. 53,54 Some of these surfaces have been used to study cell growth.…”

Tailoring Cell Adhesion Using Surface‐Grafted Polymer Gradient Assemblies

“…[16,22,26,27] While there is no consensus on the relative importance of MW and r in imparting protein resistance to a grafted polymer surface, [22,29,30] it has been demonstrated experimentally that protein adsorption systematically decreases upon an increase in either the MW and/or r of the anchored chains. [18,21,22,28] Recently, our group designed novel gradient substrates wherein polymer MW, [31] r, [32] or a combination of these two parameters, [33] can be continuously varied. Here, we utilize these polymer-gradient substrates to manipulate protein adsorption and consequently tailor the adhesion of cells.…”

Spatiotemporally Controlled Formation of Two‐Component Counterpropagating Lateral Graft Density Gradients of Mixed Polymer Brushes on Planar Au Surfaces

“…Therefore, extensive research has been dedicated to understanding the behavior of tethered polymer chains at interfaces. For instance, combinatorial approaches to surface-initiated polymerization through ATRP, have been used to probe the effects of graft density [7,20] and molecular weight [23,24] on polymer-brush surfaces. Recently, mixed or binary polymer brushes have been created by grafting two distinct polymers one after the other on the surface.…”