scholarly journals Molecular-scale structures of the surface and hydration shell of bioinert mixed-charged self-assembled monolayers investigated by frequency modulation atomic force microscopy

RSC Advances ◽  
2018 ◽  
Vol 8 (43) ◽  
pp. 24660-24664
Author(s):  
Yuki Araki ◽  
Taito Sekine ◽  
Ryongsok Chang ◽  
Tomohiro Hayashi ◽  
Hiroshi Onishi

Water molecules above a bioinert mixed-charged self-assembled monolayer (MC-SAM) surface are highly structured compared to those of bioactive SAM surfaces.

2000 ◽  
Vol 6 (S2) ◽  
pp. 726-727
Author(s):  
G. Fried ◽  
K Balss ◽  
P. W. Bohn

The electrochemical formation of gradients in self assembled monolayers has been demonstrated recently [1]. The capacity to image these gradients provides useful information on the physical chemistry of electrochemical striping.Imaging chemical gradients requires the ability to sense the chemical moiety on the top of the self-assembled monolayer. This has been accomplished by derivatizing an atomic force microscope (AFM) tip with molecules selected to have specific interactions with the sample in a technique known as chemical force microscopy [2]. Typical tapping mode AFM is then used to image the sample; the tip is oscillated vertically above the sample and the tip-sample interaction modulates the amplitude of the tip.The sample adhesion, sample stiffness, and sample topography all influence the oscillation amplitude of the tip. Pulsed Force Mode (PFM) [3] is an extension for atomic force microscopes. The PFM electronics introduces a sinusoidal modulation to the z-piezo of the AFM with an amplitude between 10 to 500 nm at a user selectable frequency between 100 Hz and 2 kHz.


2017 ◽  
Vol 28 (45) ◽  
pp. 455603 ◽  
Author(s):  
Hitoshi Asakawa ◽  
Natsumi Inada ◽  
Kaito Hirata ◽  
Sayaka Matsui ◽  
Takumi Igarashi ◽  
...  

2019 ◽  
Vol 10 ◽  
pp. 2449-2458
Author(s):  
Zhihua Fu ◽  
Tatjana Ladnorg ◽  
Hartmut Gliemann ◽  
Alexander Welle ◽  
Asif Bashir ◽  
...  

We present a new approach to study charge transport within 2D layers of organic semi-conductors (OSCs) using atomic force microscopy (AFM)-based lithography applied to self-assembled monolayers (SAMs), fabricated from appropriate organothiols. The extent of lateral charge transport was investigated by insulating pre-defined patches within OSC-based SAMs with regions of insulating SAM made from large band gap alkanethiolates. The new method is demonstrated using a phenyl-linked anthracenethiolate (PAT), 4-(anthracene-2-ylethynyl)benzyl thiolate. I–V characteristics of differently shaped PAT-islands were measured using the AFM tip as a top electrode. We were able to determine a relationship between island size and electrical conductivity, and from this dependence, we could obtain information on the lateral charge transport and charge carrier mobility within the thin OSC layers. Our study demonstrates that AFM nanografting of appropriately functionalized OSC molecules provides a suitable method to determine intrinsic mobilities of charge carriers in OSC thin films. In particular, this method is rather insensitive with regard to influence of grain boundaries and other defects, which hamper the application of conventional methods for the determination of mobilities in macroscopic samples.


2005 ◽  
Vol 871 ◽  
Author(s):  
Imma Ratera ◽  
Jinyu Chen ◽  
Amanda Murphy ◽  
Frank Ogletree ◽  
Jean M. J. Fréchet ◽  
...  

AbstractThe oligothiophene derivative (4-(5″″-tetradecyl-[2,2′;5′,2″;5″,2″′;5″′,2″″] pentathiophen-5-yl)-butyric acid (C14-5TBA) was synthesized and the structural and mechanical properties of self-assembled monolayers on mica have been studied by atomic force microscopy (AFM). The films were prepared by drop casting a dilute THF solution (1mM) of the oligothiphene on mica. Islands containing primarily monolayers with a very small percentage of multilayers were formed. The molecules adsorb through the carboxylic group, and expose the alkyl chain (CH2)13CH3. High resolution AFM scans reveal a well ordered structure of molecules with unit cell dimensions of 0.65 and 0.46 nm. Applying load to the tip, the molecular film was gradually compressed from an initial height of 4.1nm to a final one of 2.6 nm, corresponding to atilt of the alkyl chains. In regions covered with bilayers the molecules in the second layer were oriented opposite to those in the first layer, thus exposing the carboxylic end group to the air. These second layer was easily removed as the tip pressure increased.


Langmuir ◽  
1999 ◽  
Vol 15 (17) ◽  
pp. 5541-5546 ◽  
Author(s):  
Holger Schönherr ◽  
G. Julius Vancso ◽  
Bart-Hendrik Huisman ◽  
Frank C. J. M. van Veggel ◽  
David N. Reinhoudt

Sign in / Sign up

Export Citation Format

Share Document