The present investigation reports the electrochemical measurements of azurin (Az) adsorbed on a series of alkanethiol self-assembled monolayers (SAMs) under the influence of urea molecules. Theoretical fitting with the Marcus model obtains the electron-transfer rate constant, k et , and the reorganization energy, λ. When the underlying SAM is longer than 10 methylene units, k et shows an obvious chain-length dependence from which an electron-tunneling coefficient, β, of 1.09 per methylene is deduced. Combined with cyclic voltammetric results, variations of both k et and λ imply that urea impact does not penetrate into the ion core part of Az but instead influences the network of molecular hydrogen bonds. The mechanism of urea impact is further discussed by means of the pH dependence of the equilibrium potential.

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Using molecular dynamics (MD) simulation, we studied the structural transformation and breaking mechanism of a single crystalline copper nanowire under continuous strain. At a certain strain rate, an ensemble of relaxed initial states of the nanowire can preferentially go through one or more paths of deformation. In each deformation path, disordered atoms can be generated at the specific positions of the nanowire, where necking and breaking take place afterward. Such a breaking position is not predetermined; multiple initial states lead to a strain-rate-dependent, statistical distribution of breaking positions.

Theoretical investigations of a series of asymmetrically substituted conducting molecular wires [oligo(phenylene ethynylene)s] have been carried out using density functional theory and nonequilibrium Green's function formalism. To get the molecular rectification, the electron-donating group (-NH2) and the electron-withdrawing group (-NO2) are placed on the different positions of the molecular wire. The dependences of spatial distribution and lowest unoccupied molecular orbital (LUMO) energy level on the applied voltage have been found playing dominating but opposite roles in controlling the rectification behavior. In the tested bias range, since the shift LUMO energy level is more important, the electrons transfer more easily from donor to acceptor through the molecular junction in general.