Responsive polymer brushes

The combined results demonstrate the complexity of the system. Cross-linking must include kinetic contributions to the lateral resistance that are similar to those observed in the networks, but a combination of structural and dynamic factors is likely responsible for the signihcant but opposite effects from kinetically dissimilar cross-links. Stimulus-responsive polymer brush layers hold great potential (Minko et al. 2000 Motornov et al. 2003 Granville et al. 2004 Kaholek et al. 2004a,... 

Kizhakkedathu JN, Norris-Jones R, Brooks DE. Synthesis of well-defined environmentally responsive polymer brushes by aqueous ATRP. Macromolecules 2004 37 734-743. 

Minko S, Stamm M, Goreshnik E, Usov D, Sidorenko A. Environmentally responsive polymer brush layers for switchable surface properties. Pol3mi Mater Sci Eng 2000 83 533-534. 

Motomov M, Minko S, Eichhom KJ, Nitschke M, Simon F, Stamm M. Reversible tuning of wetting behavior of polymer surface with responsive polymer brushes. Langmuir 2003 19 8077-8085. 

Tokareva I, Minko S, Fendler H, Hutter E (2004) Nanosensors based on responsive polymer brushes and gold nanoparticle enhanced transmission surface plasmon resonance spectroscopy. 1 Am Chem Soc 126 15950-15951... 

The collapse of a polymer gel in response to a change in environment can be scaled down to the single chain level. A layer of polymer chains grafted to a surface forms a polymer brush, for which the collapse transition can be nicely observed using neutron reflectivity. A pore lined with a responsive polymer brush will form a selective valve for example if the grafted polymer is a weak polybase, in aqueous acidic conditions the brush will be charged and will expand to close the pore, while in basic conditions the brush will be neutral. This principle has been used to create a selective membrane, which shows greatly reduced permeability in acidic conditions. 

Surfaces that are patterned on the nano- and microscale with responsive polymer brushes are promising for applications in sensing and actuation, as well as for bioanalytical devices [42,43]. Structures of brushes, for instance, are obtained by patterning of preformed brushes using specific etching protocols or by patterning of initiators before the... 

Chen, T., Ferris, R., Zhang, J., Ducker, R., Zauscher, S. Stimulus-responsive polymer brushes on surfaces transduction mechanisms and applications. Prog. Polym. Sci. 35, 94-112 (2010)... 

Other sensitive PEMs have been described which respond to different stimuli. Photosensitive multilayers were prepared using polyelectrolytes functionalized with photoisomerizable azobenzene chromophores. Barrett et al. have prepared sensors, the mechanical properties of which change under Hght irradiation [22]. Solvent-responsive polymer brushes have been prepared by anchoring two types of polymers (one hydrophobic and one hydrophilic) on a wafer surface. As a function... 

Zhang, M. Liu, L. Zhao, H. Yang, Y Fu, G. He, B. Synthesis, characterization and application of well-defined environmentally responsive polymer brushes on the surface of colloid particles. Polymer 2001, 48, 1989-1997. 

Laloyaux, X. Fauire, E. Blin, T. Purohit, V. Leprince, J. Jouenne, T. Jonas, A. M. Glinel, K. Temperature-responsive polymer brushes switching from bactericidal to ceU-repeUenL Adv. Mater. 2010,22,5024-5028. 

Jonas, A. M. GUnel, K. Oren, R. Nysten, B. Huck, W. T. S. Thermo-responsive polymer brushes with tunable collapse temperatures in the physiological range. Macromolecules 2007,40, 4403 1405. 

Alarcon, C. D. H. Farhan, T Osborne, V. L. Huck, W. T. S. Alexander, C. Bioadhesion at micro-patterned stimuli-responsive polymer brushes. J. Mater. Chem. 2005,15, 2089-2094. 

Segal E, Perelman LA, Moore T, Kesselman E, Sailor MJ (2009) Grafting stimuli-responsive polymer brushes to freshly-etched porous silicon. Phys Status Solidi C 6 1717 Steinem C, Janshoff A, Lin VSY, Volcker NH, Ghadiri MR (2004) DNA hybridization-enhanced porous silicon corrosion mechanistic investigators and prospect for optical interferometric... 

Jia, H., Wildes, A., Titmuss, S. (2011). Structure of pH-responsive polymer brushes grown at the gold-water interface dependence on grafting density and temperature. Macromolecules, 45, 305-312. 

This chapter encompasses a review on the system of responsive polymer brushes, while specifically focusing on the large potential that these systems can have in the field of biomedical applications. 

Figure 5.6 (a) Schematic illustration of conformation changes of a pH-responsive polymer brush, (b) Response of a poly(methacrylic acid) brush (11 lun thick) modified quartz crystal... 

Figure 5.7 Schematic illustration of conformation changes of an ionic strength-responsive polymer brush.

Figure 5.13 Schematic depiction of the uptake and release of enzyme molecules into and from a responsive polymer brush.

Figure 5.20 Schematic representation of a responsive polymer brush combined with biological molecules. A change in pH, temperature, or salt concentration leads to a change between a protective state in which an enzyme and a receptor molecule are hidden away deep inside of a brush layer, and an active state in which they are exposed to the solution.

Abu-Lail, N. I., Kaholek, M., Lamattina, B., Clark, R. L., Zauscher, S. (2006). Micro-cantilevers with end-grafted stimulus-responsive polymer brushes for actuation and sensing. Sensors and Actuators B Chemical, 114, 371-378. 

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