Matrix-assisted pulsed laser deposition

Examples for the second group are polymers as fuel in the micro laser plasma thruster (JJ.LPT), PLD of polymers, matrix-assisted pulsed laser evaporation (MAPLE), which is a deposition technique that can be used to deposit highly uniform thin films [26], or laser-induced forward transfer (LIFT) [27-29], which can be used to produce microstructures by transferring an irradiated area of a target film to an acceptor substrate. The polymer can be the transferred material, or just functions as driving force in the transfer. 

Biomimetic nanocrystalline apatite coatings were deposited on titanium substrates by matrix-assisted pulsed laser evaporation (MAPLE), a technique with potential application in tissue engineering (Visan et al., 2014 Caricato etal., 2014). The targets were prepared from nano-sized, poorly crystalline apatite powders, analogous in composition to mineral bone. For the deposition of thin films, a KrF excimer laser source was used (A = 248 nm,rFWHM < 25 ns). Analyses of the deposited films showed that the structural and chemical nature of the nanocrystalline precursor apatite was preserved. Hence, MAPLE may be a suitable technique for the congruent transfer of a delicate material such as nanohydroxyapatite. 

A. M. Taurino, R. Rella, J. Spadavecchia, M.G. Manera, S. Capone, M. Martino, A.P. Caricato, T. Tunno, Acetone and ethanol solid-state gas sensors based on Ti02 nanoparticles thin film deposited by matrix assisted pulsed laser evaporation , Sensors and Actuators B, 127, 426 31, (2007). 

Cristescu R, Popescu C, Popescu AC, Mihailescu IN, Ciucu AA, Andronie A, lordache S, Stamatin 1, Fagadar-Cosma E, Chrisey DB. Eunctional porphyrin thin films deposited by matrix assisted pulsed laser evaporation. Mater Sci Eng B 2010 169 106-10. 

During the last decade, processing of polymers has become an important field of applied and fundamental research [48]. One of the most important fields is laser ablation involving various techniques and applications. Laser ablation is used as an analytical tool for MALDI (matrix-assisted laser de-sorption/ionization) [28, 29] and LIBS (laser-induced breakdown spectroscopy) [49] or as a preparative tool for PLD (pulsed laser deposition) of inorganic materials [37] and of synthetic polymer films [50, 51]. Another application is surface modification of polymers [52] if low fluences are applied, the polymer surface can be either chemically modified to improve adhesion... 

Since its discovery, laser polymer processing has become an important field of applied and fundamental research. The research can be separated into two fields, the investigation of the ablation mechanism and its modeling and the application of laser ablation to produce novel materials. Laser ablation is used as an analytical tool in matrix-assisted laser desorption/ionization (MALDI) [12,13] and laser-induced breakdown spectroscopy (LIBS) [14] or as preparative tool for pulsed laser deposition (PLD) of synthetic polymers [15,16] and of inorganic films [17,18],... 

The mass spectrometry analysis was performed by the matrix assisted laser desorption/ionisation time-of-flight (S8-MALDI) technique using a Voyager-DE PRO Biospectrometry Workstation (Applied Biosystems, USA). Radiation pulses of 0.5 ns and 3 Hz frequency from N2 laser operating at 337 nm were used to desorb the species and negative/positive ions formed were detected in reflectron mode. Sulfur used as a matrix material was also dissolved in toluene and mixed with the samples solution prior to deposition onto a target. 

MALDI-MS refers to matrix-assisted laser desorption-ionization mass spectroscopy, It is also called MALFI-TOF, because the mass spectrometer is a time-of-flight version. In this technique, the polymer is mixed with a molar excess of a salt, for cationization, and deposited on a probe surface. A UV laser is pulsed... 

Matrix-assisted laser desorption ionization (MALDI) In MALDI, the polymer is mixed intensively (usually from a solution) with a matrix, and possibly with other additives such as a salt. It is then deposited as a small spot on a target (MALDI plate). The deposited mixture is irradiated by a laser pulse. The matrix is selected such that it strongly adsorbs the laser light, heats up very rapidly, and induces the transfer of a single charge (usually an adduct ion) to the polymer molecule. The... 

Laser Desorption/Ablation Ionization Methods. Matrix-assisted laser desoiption ionization (MALDI) relies on the use of a solid chromophQric matrix, chosen to absorb laser light, which is co-mixed with the analyte (4). Typically, a solution of a few picomoles of analyte is mixed widi a lOO-to-5000 fold excess of the matrix in solution. A few microliters of the resulting solution are deposited on a mass spectrometer solids probe, and the solvent is allowed to evaporate before inserting the probe into the mass spectrometer. When the pulsed laser beam strikes the sample surface in the spectrometer, the sample molecules are desorbedAonized at high efficiency. The various mechanisms for matrix and non-matrix assisted laser desorption have been discussed (5,6). 

---