Surface-to-Surface Bridges Formed by Reversibly Assembled Polymers

Abstract

Self-assembled polymers whose main chains are defined by reversible DNA base pairing form bridges between the tip of an atomic force microscope and substrate. The forces associated with the rupture of these assemblies are independent of polymer bridge length, and they resemble those expected for the isolated associations defining the polymer bridges. The assembly is reversible and is inhibited by a competitive, nonpolymerizing oligonucleotide. Noncomplementary polymer brush layers do not bridge, and therefore, the forces result from specific molecular recognition events. The length distribution of the bridges differs greatly from that of the polymers in solution, and thus the bridging is responsive to the spatial constraints of the environment.

Rational Control of Viscoelastic Properties in Multicomponent Associative Polymer Networks

“…More generally, the results presented here speak to the potential of reversible and specific intermolecular interactions as effectors of the entanglements or polymer bridges 38,39,53 necessary to transmit force in materials. The sophistication available in the field of molecular recognition holds considerable promise as it is applied increasingly to areas of material science.…”

“…We have recently explored molecular mechanisms underlying the mechanical properties of both linear SP's [36][37][38][39][40] and SP networks. 41,42 The SP networks were formed via specific metal-ligand coordination between bis-Pd(II) and Pt(II) organometallic cross-linkers and poly (4-vinylpyridine), PVP, in DMSO.…”

Metallo-supramolecular modules as a paradigm for materials science

“…Note that this work shows how dynamics and mechanism of metal-ligand exchange reactions are not only a qualitative but also a quantitative representation of the viscoelastic properties of bulk materials [78]. Although thermodynamics are a primary design consideration in supramolecular chemistry, the dynamics of the interactions are particularly important under nonequilibrium conditions, such as those imposed under mechanical stress [76,77,79]. Recently, Craig and coworkers used single-molecule force spectroscopy to study the mechanical activation of the ligand substitution reaction.…”

Evaluation of viscosity and shear stress in a telechelic polymer when various shear rates are applied

“…In turn, associating polymers comprise an important class within the much broader field of selforganizing soft materials or structured fluids (block copolymers, high-and low-molecular-weight liquid crystals, and lyotropic and amphiphilic systems) [2][3][4][5][6][7]. The association may be induced by several types of physical interaction: hydrogen bonding, a hydrophobic interaction between alkyl or aromatic groups [8], an association of perfluorated chains [9], electrostatic forces (ionomers) [7][8][9][10], complex formation, or supramolecular adducts [11,12].…”