Mapping mechanical properties of organic thin films by force-modulation microscopy in aqueous media

• Jianming Zhang,
• Zehra Parlak,
• Carleen M. Bowers,
• Terrence Oas and
• Stefan Zauscher

Beilstein J. Nanotechnol. 2012, 3, 464–474, doi:10.3762/bjnano.3.53

• section for details). The sample was backfilled with thiol molecules at high concentration for different lengths of time. An EG3-thiol SAM is about 2.4 nm thick when thiols are in a close-packed configuration, while the thickness is only about 0.4 nm when the thiol chains lie flat on the surface [63

• concentration generates low-grafting-density patterns. (c) Residual negative resist is stripped off by solvent washing. (d) Newly exposed gold surface is covered by high-grafting-density EG3 thiol by backfilling. (e) Overnight exposure to EG3 solution equilibrates the patterned-thiol SAM to a uniform surface

Colloidal lithography for fabricating patterned polymer-brush microstructures

• Tao Chen,
• Debby P. Chang,
• Rainer Jordan and
• Stefan Zauscher

Beilstein J. Nanotechnol. 2012, 3, 397–403, doi:10.3762/bjnano.3.46

• obtained by sputter deposition of the metal [2][4]. When gold is chosen as the metal, the ensuing pattern can be easily functionalized chemically with a self-assembled monolayer (SAM) of a thiol initiator, which can be subsequently amplified into polymer brushes. Figure 1 shows this strategy for the

• between the microspheres (Figure 1A). After the microsphere mask was removed by sonication, an array of hexagonally arranged triangular gold islands remained (Figure 1B) on which we formed a SAM of thiol initiator (BrC(CH3)2COO(CH2)11SH) [27]. We then synthesized poly(N-isopropylacrylamide) (PNIPAAM

• a range of microstructures [28]. Colloidal microspheres have an inherently curved surface that can serve as a template for spreading alkanethiol molecules along the surface of the microspheres onto the gold substrate surface, creating a ring-shaped SAM feature around the footprint of the sphere

Functionalised zinc oxide nanowire gas sensors: Enhanced NO₂ gas sensor response by chemical modification of nanowire surfaces

• Eric R. Waclawik,
• Jin Chang,
• Andrea Ponzoni,
• Isabella Concina,
• Dario Zappa,
• Elisabetta Comini,
• Nunzio Motta,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2012, 3, 368–377, doi:10.3762/bjnano.3.43

• & Brescia University, Chemistry & Physics Department, Via Valotti 9, 25133 Brescia, Italy 10.3762/bjnano.3.43 Abstract Surface coating with an organic self-assembled monolayer (SAM) can enhance surface reactions or the absorption of specific gases and hence improve the response of a metal oxide (MOx

• target are positive results arising from the coating of these ZnO nanowire sensors with organic-SAM-functionalised ZnO nanoparticles. Keywords: gas sensor; nanowire; tris(hydroxymethyl)aminomethane; self-assembled monolayer; zinc oxide; Introduction Semiconductor gas sensors have been extensively

• through organic SAM functionalisation of the semiconductor surface is a chemical effect. Since only the outermost 5 Å of a surface completely determines its chemical properties, that is whether it is hydrophobic, hydrophilic, acidic, or basic for example, surface functionalisation with an organic molecule

Variations in the structure and reactivity of thioester functionalized self-assembled monolayers and their use for controlled surface modification

• Inbal Aped,
• Yacov Mazuz and
• Chaim N. Sukenik

Beilstein J. Nanotechnol. 2012, 3, 213–220, doi:10.3762/bjnano.3.24

• the composition and chemistry of solid interfaces. First introduced by Jacob Sagiv and co-workers [1][2][3], siloxane-anchored SAMs have been used to modify the wetting and composition of variously hydroxylated surfaces. In situ chemical transformations of the SAM surfaces provide an additional

• dimension to the versatility and utility of the SAMs [4][5][6][7]. Our laboratory has reported in situ transformations of siloxane-anchored SAMs in which SAM surface functionality was changed from benzene rings to arylsulfonic acids [8][9], from nitrate esters to hydroxyls [10], and from carboxylate esters

• reported. A striking example of in situ SAM transformations is based on the initial deposition of thioacetate-bearing monolayers and their in situ conversion to sulfonic acid surfaces [15]. This transformation provides the basis for surface patterning of the monolayer and for its use as a patterned

Self-assembly of octadecyltrichlorosilane: Surface structures formed using different protocols of particle lithography

• ChaMarra K. Saner,
• Kathie L. Lusker,
• Zorabel M. LeJeune,
• Wilson K. Serem and
• Jayne C. Garno

Beilstein J. Nanotechnol. 2012, 3, 114–122, doi:10.3762/bjnano.3.12

• to optimize the deposition conditions for achieving a densely packed SAM. Images of a nanostructured film of OTS prepared by using particle lithography combined with contact printing are shown in Figure 4. A honeycomb arrangement of nanopores is shown in Figure 4a, with approximately 25 × 20 rows of

Electron-beam patterned self-assembled monolayers as templates for Cu electrodeposition and lift-off

• Zhe She,
• Andrea DiFalco,
• Georg Hähner and
• Manfred Buck

Beilstein J. Nanotechnol. 2012, 3, 101–113, doi:10.3762/bjnano.3.11

• ) adsorbed on polycrystalline gold substrates served as templates to control electrochemical deposition of Cu structures from acidic solution, and enabled the subsequent lift-off of the metal structures by attachment to epoxy glue. By exploiting the negative-resist behaviour of MBP0, the SAM was patterned by

• single component SAM is an alternative that is particularly attractive for providing access to the nanoscale, since e-beam lithography as a high-resolution technique can be employed [26][30]. However, the effect is strongly dependent on the type of SAM [25][30][39][40]. Aliphatic SAMs degrade upon

• exposure to electrons (positive-resist behaviour), in contrast to aromatic SAMs in which the molecular structure of the SAM is essentially preserved [40] apart from the cross-linking of the aromatic moieties. The rather ill-defined electron-induced degradation of aliphatic SAMs makes it very difficult to

Substrate-mediated effects in photothermal patterning of alkanethiol self-assembled monolayers with microfocused continuous-wave lasers

• Anja Schröter,
• Mark Kalus and
• Nils Hartmann

Beilstein J. Nanotechnol. 2012, 3, 65–74, doi:10.3762/bjnano.3.8

• routines in micro- and nanopatterning of different types of SAMs and other ultrathin organic coatings [11][18][19][20][21][22][23][24][25][26][27][28]. Because of the photothermal process, the performance of such laser techniques depends on both the peculiar chemical structure of the SAM, notably the

• , thermal desorption of the thiol molecules is initiated [11]. Subsequently, the Au layer in these laser-depleted surface areas was removed by means of wet-chemical etching [11][29]. For this purpose, the patterned substrates were immersed into an aqueous solution of K2S2O3 and K3Fe(CN)6. The HDT SAM acts

• complications, such as surface melting and substrate ablation. Hence, the procedure has to be carefully optimized in order to ensure selective processing of the SAM [11][24]. Calculated surface-coverage profiles at a typical laser pulse length of τ = 1 ms are displayed in Figure 7. Clearly, an increase in the

Direct-write polymer nanolithography in ultra-high vacuum

• Woo-Kyung Lee,
• Minchul Yang,
• Arnaldo R. Laracuente,
• William P. King,
• Lloyd J. Whitman and
• Paul E. Sheehan

Beilstein J. Nanotechnol. 2012, 3, 52–56, doi:10.3762/bjnano.3.6

• materials (e. g., metals [11], nanoparticles [12], and SAM molecules [10]) have been deposited using this technique. Thermal DPN closely mirrors the capabilities of conventional DPN but with greater control over the ink flow [5]. Critically, the heat from the probes enables the deposition of high melting

Effect of the tip state during qPlus noncontact atomic force microscopy of Si(100) at 5 K: Probing the probe

• Adam Sweetman,
• Sam Jarvis,
• Rosanna Danza and
• Philip Moriarty

Beilstein J. Nanotechnol. 2012, 3, 25–32, doi:10.3762/bjnano.3.3

• Adam Sweetman Sam Jarvis Rosanna Danza Philip Moriarty School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, U.K. 10.3762/bjnano.3.3 Abstract Background: Noncontact atomic force microscopy (NC-AFM) now regularly produces atomic-resolution images on a wide range of

X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

• Hicham Hamoudi,
• Ping Kao,
• Alexei Nefedov,
• David L. Allara and
• Michael Zharnikov

Beilstein J. Nanotechnol. 2012, 3, 12–24, doi:10.3762/bjnano.3.2

• anchor and the nitrile tail groups located at the SAM–ambient interface. The packing density in these SAMs was found to be close to that of alkanethiolate monolayers on Au(111), independent of the chain length. Similar behavior was found for the molecular inclination, with an average tilt angle of ~33–36

• [12][13][14][15][16][17][18], in-wire junctions [9], and cross-nanowire junctions [19]. For most of these measurements the molecular wires were assembled on a conductive substrate, serving as the bottom electrode, by using self-assembled monolayer (SAM) methods. For this purpose, oligomeric chains

• were combined with a suitable anchor (head) group having a strong affinity to the selected substrate. The most frequently used group in this regard is thiol, which allows SAM-like assembly of the molecules on coinage metal and various semiconductor substrates, for example Au and GaAs, respectively

Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

• Yaron Paz

Beilstein J. Nanotechnol. 2011, 2, 845–861, doi:10.3762/bjnano.2.94

• alkylsilane SAM having a terminal amine, was observed to be lower on a TiO2 substrate than on a SiO2 substrate [19]. Here, it was claimed by the authors that the more ionic character of the Ti–O bond may require higher energies to form Ti–OH groups, leading to lower density of surface hydroxyls unless an

• -monoalkanephosphate SAMs and TiO2 was presented by Chen et al. who claimed, based on XPS measurements, that this type of SAM can be bonded to the TiO2 surface by way of both monodentate and bidentate coordination [30]. Accordingly, it was claimed that the monodentate and the bidentate of adjacent phosphate headgroups

• relatively weak carbamate linkage with the surface [32]. Here, water contact-angle hysteresis for the SAM-covered TiO2 surfaces were found to be larger than that observed for the SAM-covered SiO2 surface, suggesting that alkyl isocyanate SAMs on TiO2 were more disordered and/or were less densely packed

Direct monitoring of opto-mechanical switching of self-assembled monolayer films containing the azobenzene group

• Einat Tirosh,
• Enrico Benassi,
• Silvio Pipolo,
• Marcel Mayor,
• Michal Valášek,
• Veronica Frydman,
• Stefano Corni and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2011, 2, 834–844, doi:10.3762/bjnano.2.93

• molecular-level mechanical manipulators. As an example, macroscopic transport at the solid–liquid interface was driven by modifying the solid–liquid surface tension at a droplet front by using a molecular switch based on a SAM of rotaxane [8]. Central to the function of such systems are changes in the inter

• atomic force microscopy (AFM) and atomistic computational study of the change in local stiffness, as induced by the optical cis↔trans conversion in a SAM of 4'-{[(1,1'-biphenyl)-4-yl]diazenyl}-(1,1'-biphenyl)-4-thiol (thio-2-DA). The experimental variation in stiffness shows quantitative agreement with

• -DA molecules bind only to the gold, such that each scan line contains regions of hard surface (glass) and soft surface (SAM/Au). Figures 1–3 show how this concept is used to generate data. For each horizontal scan line, both the glass substrate and the gold island are sampled. For purposes of this

Mechanical characterization of carbon nanomembranes from self-assembled monolayers

• Xianghui Zhang,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2011, 2, 826–833, doi:10.3762/bjnano.2.92

• Young’s modulus of 6–8 GPa and 8–10 GPa, respectively. CBPS CNMs that were formed from a SAM on silicon nitride showed a similar elastic behavior with a Young’s modulus of 10–12 GPa. Note that CBPS SAMs are distinct from BPT and NBPT SAMs not only in the substrate, but also in the head group. Furthermore

Effect of the environment on the electrical conductance of the single benzene-1,4-diamine molecule junction

• Shigeto Nakashima,
• Yuuta Takahashi and
• Manabu Kiguchi

Beilstein J. Nanotechnol. 2011, 2, 755–759, doi:10.3762/bjnano.2.83

• solution. For comparison, the conductance measurement was also performed without solution. A self-assembled monolayer (SAM) of BDA on the Au substrate was prepared by exposing the substrate to methanol solution containing 10 mM BDA overnight. The conductance measurements were performed in N2 gas. Results

Tip-enhanced Raman spectroscopic imaging of patterned thiol monolayers

• Johannes Stadler,
• Thomas Schmid,
• Lothar Opilik,
• Phillip Kuhn,
• Petra S. Dittrich and
• Renato Zenobi

Beilstein J. Nanotechnol. 2011, 2, 509–515, doi:10.3762/bjnano.2.55

• Raman spectroscopy (TERS) was used to measure the distribution of two isomeric thiols (2-mercaptopyridine (2-PySH) and 4-mercaptopyridine (4-PySH)) in a self-assembled monolayer (SAM) on a gold surface. From a patterned sample created by microcontact printing, an image with full spectral information in

• analyte in a short time, allowing acquisition of Raman images of a surface area covered with weakly scattering molecules. The information from such a Raman image was used here to chemically identify and localize two different thiol isomers in an inhomogeneous self-assembled monolayer (SAM). In this work

• surfaces or certain surface areas. Here, selected areas on a gold surface were modified by a thiol and, in a second step, the remaining substrate was covered by a secondary thiol film. This type of surface can act as a basis for biosensors [12][13]. To produce patterned SAM structures on a gold surface

Towards multiple readout application of plasmonic arrays

• Dana Cialla,
• Karina Weber,
• René Böhme,
• Uwe Hübner,
• Henrik Schneidewind,
• Matthias Zeisberger,
• Roland Mattheis,
• Robert Möller and
• Jürgen Popp

Beilstein J. Nanotechnol. 2011, 2, 501–508, doi:10.3762/bjnano.2.54

• nonspecific interaction of the DNA strands with the gold surface, through the nitrogen atoms of the DNA bases, was prevented by the formation of an octanethiol SAM as a lipophilic protection layer. Dye-labeled target DNA was incubated on the chip surface and bound efficiently to the complementary capture

• conditions (35 W, 30 s) before usage. To prevent nonspecific interactions of the DNA strands with the metallic surface through the DNA bases, the plasmonic arrays were incubated in a 10 mM ethanolic solution of octanethiol, providing a lipophilic protection layer (here: Self assembled monolayer (SAM)) on the

Influence of water on the properties of an Au/Mpy/Pd metal/molecule/metal junction

• Jan Kučera and
• Axel Groß

Beilstein J. Nanotechnol. 2011, 2, 384–393, doi:10.3762/bjnano.2.44

• containing metal cations is brought into contact with a self-assembled monolayer (SAM) consisting of organic molecules on a metal substrate, thus forming metal cation/molecule complexes. Then the cationic solution is exchanged with a cation-free electrolyte, and the cation/molecule complexes are reduced

• under potential control resulting in a metal layer on top of the SAM. The application of this technique led recently to the preparation of various metal/SAM/metal junctions on Au(111) electrodes, involving SAMs formed by 4-mercaptopyridine (Mpy) [1], 4-aminothiophenol (ATP) [2], thiazole [3], or 1,4

• design of future bionanoelectronics in which the organic (molecule) and inorganic (metal) units will communicate with each other. Yet, there are many fundamental questions open with respect to the factors that play a crucial role in the preparation, characterization, and operation of metal/SAM/metal