Patterned polymer brushes

The advantage of this approach is not only the free choice of surface stractures which can be created, the material contrast which can be realized by the combination of chemical lithography and amplification with SIP, but also the potential to bridge the gap in structural feature sizes ranging from the microscopic to the nano-scopic scale. Since the feature sizes reported are still limited to the features of the mask used, direct writing with a focused e-beam should result in patterned polymer brushes of features matching the size of the immobilized macromolecule. 

In a series of papers, Matsuda et al. [291-295] employed RAFT-SIP with immobilized benzyl N,N-diethyldithiocarbamate to form polymer brushes from styrene, methacrylamides, acrylamides and acrylates, NIPAM and N-vinyl-2-pyrrolidone on various surfaces. The SIP is initiated by UV irradiation of the surface-bonded dithiocarbamates. Thermoresponsive polymer brushes were prepared by the polymerization of NIPAM and investigated by XPS, wetting experiments and mainly SPM [294]. Patterned polymer brush layers were also prepared. When chloro-methyl styrene was used as a comonomer, RAFT-SIP resulted in branching. By control of the branching, spatio-resolved hyperbranching of a controllable stem/ branch design was realized (Fig. 9.32) [293, 295]. 

Fig. 7 (a) Growth of temperature-dependent, patterned polymer brushes on SAMs on gold surfaces. Images show adhesion of (b) FITC-BSA after incubation at 37°C and rinse at 12°C (c) S. mutans after incubation at 4°C for 1 h and (d) S. mutans after incubation at 37°C for 1 h. Reproduced from [112] with permission. Copyright The Royal Society of Chemistry, 2005... 

Figure 6. Interaction of a water droplet with 200 micron features of a patterned polymer brush prepared by surface-initiated polymerization. The unusual wetting profile is due to preferential interaction of the water droplet with the polymery lie acid) brush domains (light) and complete non-wetting of the hydrophobic poly(tert-butyl acrylate) domains (dark).

Welch ME, Ober CK. Responsive and patterned polymer brushes. J Polym Sci B Polym Phys 2013 51(20) 1457-72. 

Farhan T, Huck WTS. Synthesis of patterned polymer brushes from flexible polymeric films. Eur Polym J 2004 40(8) 1599-604. 

Nakayama and coworkers presented two different strategies for obtaining patterned polymer brushes on PET and PS [12]. In the first approach, a styrene-based polymer with photoreactive RAFT initiators was synthesized and spincoated on PET (Figure 3.7A). Alternatively,... 

NBE strands from the surface [180]. Furthermore, anodization lithography was used to prepare nano-patterned polymer brushes on silicone [181], and the resulting nano-particles were functionalized by SI-ROMP [182]. SI-ROMP has been conducted using low-strain monomers such as CPE or cyclododecene to prepare polymer brushes [183]. SI-ROMP has also been conducted on cellulose fibers [184] as well as for the preparation of functional supports and materials [185-187]. 

Chen T, Amin I, Jordan R (2012) Patterned polymer brushes. Chem Soc Rev 41(8) 3280... 

Locklin and coworkers have intensively researched post-polymerization modification via click chemistry for the design of complex surfaces [41, 99-106]. The patterning of polymer-grafted planar surfaces was carried out by consecutive functionalization using the same click-type reaction or multiple click-type reactions. One example is a spatially patterned polymer brush surface fabricated by the combination of surface-initiated free-radical polymerization (Sl-LRP) and... 

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