  Self-Assembled Film Organization in Fast Microcontact Printing Investigated by Sum Frequency Generation Spectroscopy; ; et al in Journal of Physical Chemistry C: Nanomaterials, Interfaces, and Hard Matter (2009), 113 The ability of microcontact printing to build highly ordered alkanethiol self-assembled monolayers (SAMs) on Pt substrates within a short time is studied by sum frequency generation (SFG) spectroscopy and ... [more ▼] The ability of microcontact printing to build highly ordered alkanethiol self-assembled monolayers (SAMs) on Pt substrates within a short time is studied by sum frequency generation (SFG) spectroscopy and contact angle measurements. The deposition of ordered hexadecanethiol and dodecanethiol monolayers onto platinum substrates is achieved in less than 1 s. The film order and the alkane chain orientation are deduced from the SFG fingerprint acquired under different sets of laser polarization. Comparisons between the SAMs prepared by printing or by immersion demonstrate that both methods lead to the same high quality organization. Patterning effects within printed films are also investigated with respect to the layer conformation. Finally, wetting properties of printed layers are correlated with the printing duration, corroborating the spectroscopic results. [less ▲] Detailed reference viewed: 35 (4 ULg)DC Magnetron Sputtering Deposition of Titanium Oxide Nanoparticles: Influence of Temperature, Pressure and Deposition Time on the Deposited Layer Morphology, the Wetting and Optical Surface PropertiesDreesen, Laurent  ; ; in Plasma Processes and Polymers (2009), 6 Titanium dioxide nanoparticles were prepared on glass substrates by reactive DC magnetron sputtering. As highlighted by the atomic force microscopy characterization, we were able to control the ... [more ▼] Titanium dioxide nanoparticles were prepared on glass substrates by reactive DC magnetron sputtering. As highlighted by the atomic force microscopy characterization, we were able to control the nanoparticles' surface coverage and diameter by varying the deposition time and the total pressure, respectively. The titanium dioxide energy band gap, determined by using ultraviolet-visible, spectroscopy, depends on the total pressure but is quite independent of the deposition temperature. On the contrary, it is blue shifted when the pressure increases. Finally, the contact angles slightly decrease after ultraviolet illumination irrespective of the different deposition parameters, indicating an improvement of the hydrophilic properties of the adsorbed layer. After 21 h in dark, the contact angles are nearly identical to the ones before exposure to UV light: the samples do not keep their hydrophilic behaviour. [less ▲] Detailed reference viewed: 46 (7 ULg)Reactive DC magnetron sputtering deposition of titanium oxide nanoparticles : influence of the process parameters on the morphology and the surface coverageDreesen, Laurent ; ; Conference (2008, October) Detailed reference viewed: 11 (1 ULg)DC magnetron sputtering deposition of titanium oxide nanoparticles : influenceDreesen, Laurent ; ; Conference (2008, September) Detailed reference viewed: 14 (4 ULg)A generic chemical platform for molecular recognition and stimuli-responsive probes based on scanning probe microscopy; Lussis, Perrine ; Jérôme, Christine et alin Small : Nano Micro (2008), 4(8), 1101-1104 The grafting of poly-N-succinimidyl acrylate from scanning probe microscopy tips is shown to be a robust platform for the very easy elaboration of versatile probes with sensor capabilities and tunable ... [more ▼] The grafting of poly-N-succinimidyl acrylate from scanning probe microscopy tips is shown to be a robust platform for the very easy elaboration of versatile probes with sensor capabilities and tunable properties. The modified tips can be easily postfunctionalized for single-molecule recognition of host-guest and ligand-receptor systems and for the design of smart probes that are thermo- and pH-responsive. [less ▲] Detailed reference viewed: 124 (24 ULg)Atomic force microscopy investigation of the morphology and the biological activity of protein-modified surfaces for bio- and immunosensors; Duwez, Anne-Sophie ; Gabriel, Sabine et alin Analytical Chemistry (2007), 79(17), 6488-6495 With the purpose of developing biosensors, the reliable proof of the biological activity of two new sensor systems was obtained by atomic force microscopy (AFM) in both the imaging and the single-molecule ... [more ▼] With the purpose of developing biosensors, the reliable proof of the biological activity of two new sensor systems was obtained by atomic force microscopy (AFM) in both the imaging and the single-molecule force spectroscopy modes. Antigens or antibodies of pharmacological interest were grafted onto self-assembled monolayers of thiols on gold, and AFM imaging demonstrated that the grafting process produced homogeneous submonolayers of isolated proteins. The analysis of the morphology of the surfaces at the different functionalization steps allowed evaluating the protein grafting density and showed that the recognition of complementary species present in the surrounding solution occurred. Single-molecule force spectroscopy experiments between the sensing surfaces and AFM probes, onto which the complementary species were grafted, enabled a direct and rapid test of the biological activity of the sensors by investigating the interaction occurring at the level of one single ligand-receptor bond. Ellipsometry and surface plasmon resonance allowed further characterization of the sensor surfaces and confirmed that the biological recognition took place. [less ▲] Detailed reference viewed: 38 (13 ULg)Orientation and Order of Self-Assembled p-Benzenedimethanethiol Films on Pt(111) Obtained by Direct Adsorption and via Alkanethiol Displacement; Dreesen, Laurent ; et alin Journal of Physical Chemistry C: Nanomaterials, Interfaces, and Hard Matter (2007), 111 Self-assembly of p-benzenedimethanethiol (p-BDMT) on Pt(111) has been investigated by high-resolution electron energy loss spectroscopy and sum-frequency generation spectroscopy. The molecules adsorb on ... [more ▼] Self-assembly of p-benzenedimethanethiol (p-BDMT) on Pt(111) has been investigated by high-resolution electron energy loss spectroscopy and sum-frequency generation spectroscopy. The molecules adsorb on Pt-(111) like on gold, attached through one single thiol, leaving the second thiol moiety unreacted and exposed to the outer surface. Yet, the order of the p-BDMT self-assembled film is poor in comparison to alkanethiol SAMs. Displacement in solution of a preadsorbed pentanethiol (PTT) SAM by p-BDMT molecules proved to be a successful approach to achieve films of higher quality, where the size of the dithiol molecular domains tends toward the size measured for PTT. Nearly complete exchange is accomplished after 42 h. However, no significant exchange is observed when dodecanethiol replaces PTT. Displacing the alkanethiols by benzenethiol leads to the same conclusions, suggesting that the exchange processes are lessened as compared to gold. [less ▲] Detailed reference viewed: 17 (1 ULg)A generic platform for SPM-based molecular recognition processes and stiluli-responsive probesGabriel, Sabine ; Jérôme, Christine ; et alPoster (2006, May 18) Detailed reference viewed: 10 (1 ULg) |
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