AFM study of cationically charged polymer brushes: switching between soft and hard matter

Tunable Wettability by Clicking Counterions Into Polyelectrolyte Brushes

“…In addition, not only the wetting properties are modified: significant changes in the nanomechanical properties of the organic film were also observed. [29] Counterion-dependent properties of quaternary ammonium salts have been observed by chemists for many years. In the case of QA + -containing cationic-exchange resins, different anions lead to significant differences in affinities or retention times.…”

“…This is the origin of the sharp change in wettability upon coordination of ClO 4 -with the brushes, where the anion confers its hydrophobic characteristics to the brush layer. [13,29] Within the traditional picture of polyelectrolyte brushes, the presence of counterions is mostly associated with the electrostatic screening of pendant charges by means of highly mobile counterions. However, in the case of strongly ion-paired species the brush experiences not only an electrostatic change, but also a drastic chemical change (hydrophilic-hydrophobic).…”

Responsive Polymers at the Biology/Materials Science Interface

“…These include artificial muscle, nanoactuators, and combinations of molecular recognition, binding, release, and motor systems. [18][19][20] Pennadam and co-workers recently reported a reversibly responsive DNA translocating motor, based on a bacterial restriction-modification (RM) enzyme, EcoR124. [20] The enzyme, powered by adenosine triphosphate (ATP), is capable of binding and moving DNA, which subsequently leads to nucleic acid restriction.…”

Microphase‐Separated Brushes on Square Platelets in PS‐b‐PEO Thin Films

“…The effect of the thermal history of the solution used for spin-coating on the morphology of the thin film obtained (Supporting Information, Figure S2) indicates the kinetic influences. [2] When T i < T m (46 8C, Figure 1a and c), microphaseseparated brushes on square-shaped platelets surrounded by microphase-separated structures in the thin film can be observed. The crystallization behavior of the platelet is shown by the electron diffraction spots, which are attributed to the two (120) planes (inset of Figure 1a).…”

“…[1][2][3][4][5][6][7] Polymer brushes refer to an assembly of polymer chains which are tethered at one end to a surface or interface. [3] Theoretical studies using self-consistent-field calculations, scaling arguments, and computer simulations have indicated that tethered block copolymer brushes exhibit complex behaviors that depend on many factors.…”