| 505 |
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 506 |
|
\subsection{Effect of Mixed Chain Lengths} |
| 507 |
|
|
| 508 |
< |
Previous work demonstrated that for butanethiolate monolayers on a Au(111) surface, the interfacial conductance was a non-monotonic function of the percent coverage. This is believed to be due to enhanced solvent-thiolate coupling through greater penetration of solvent molecules into the thiolate layer. At lower coverages, hexane solvent can more penetrate into the interfacial layer by fitting into gaps between the thiolates. However, a side effect of low coverages is surface aggregation of the thiolates. To simulate the effect of low coverages while preventing thiolate domain formation, we maintain 100\% thiolate coverage while varying the proportions of short (butanethiolate, n = 4) and long (decanethiolate, n = 10 or dodecanethiolate, n = 12). In systems where there is a mix of short and long chain thiolates, interfacial conductance is a non-monotonic function of the percent of long chains. |
| 508 |
> |
Previous work demonstrated that for butanethiolate monolayers on a Au(111) surface, the interfacial conductance was a non-monotonic function of the percent coverage. This is believed to be due to enhanced solvent-thiolate coupling through greater penetration of solvent molecules into the thiolate layer. At lower coverages, hexane solvent can more penetrate into the interfacial layer by fitting into gaps between the thiolates. However, a side effect of low coverages is surface aggregation of the thiolates. To simulate the effect of low coverages while preventing thiolate domain formation, we maintain 100\% thiolate coverage while varying the proportions of short (butanethiolate, n = 4) and long (decanethiolate, n = 10 or dodecanethiolate, n = 12) thiolate alkyl chains. In systems where there is a mix of short and long chain thiolates, interfacial conductance is a non-monotonic function of the percent of long chains. |
| 509 |
|
|
| 510 |
|
\begin{figure} |
| 511 |
|
\includegraphics[width=\linewidth]{figures/Gstacks} |
| 514 |
|
\end{figure} |
| 515 |
|
|
| 516 |
|
\subsubsection{Butanethiolate/Decanethiolate} |
| 517 |
< |
Mixtures of butanethiolate/decanethiolate (n = 4, 10) have a peak interfacial condutance for 25\%/75\% short/long chains. |
| 517 |
> |
Mixtures of butanethiolate/decanethiolate (n = 4, 10) have a peak interfacial conductance for 25\%/75\% short/long chains. |
| 518 |
|
|
| 519 |
|
\subsubsection{Butanethiolate/Dodecanethiolate} |
| 520 |
|
Mixtures of butanethiolate/dodecanethiolate (n = 4, 12) have a peak interfacial conductance for 12.5\%/87.5\% short/long chains. |
| 558 |
|
\end{equation} |
| 559 |
|
where T is the length of the simulation. This is a direct measure of |
| 560 |
|
the rate at which solvent molecules entangled in the thiolate layer |
| 561 |
< |
can escape into the bulk. As $k_{escape} \rightarrow \infty$, the |
| 561 |
> |
can escape into the bulk. As $k_{escape} \rightarrow 0$, the |
| 562 |
|
solvent has become permanently trapped in the thiolate layer. In |
| 563 |
|
figure \ref{fig:Gstacks} we show that interfacial solvent mobility |
| 564 |
|
decreases as the percentage of long thiolate chains increases. |
| 619 |
|
as a function |
| 620 |
|
|
| 621 |
|
|
| 622 |
+ |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 623 |
+ |
% **CONCLUSIONS** |
| 624 |
+ |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 625 |
+ |
\section{Conclusions} |
| 626 |
+ |
|
| 627 |
+ |
|
| 628 |
+ |
|
| 629 |
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 630 |
|
% **ACKNOWLEDGMENTS** |
| 631 |
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
