Untitled

Martinsons, Christophe; Levick, A. P.; Edwards, G. J.

doi:10.1023/a:1025073506015

Cited by 11 publications

(6 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The thermal wave propagates from the irradiated volume into the sample at a rate determined by the thermal diffusivity of the material, D = 0.25 cm 2 s -1 for Pt, 47 which leads to a heat diffusion length of ca. l th = 0.7 µm during the 5 ns pulse duration of the ablating laser.…”

Section: Ablation Process and Nanoparticle Growth Mechanismsmentioning

confidence: 99%

Platinum Nanoparticles as Photoactive Substrates for Mass Spectrometry and Spectroscopy Sensors

et al. 2014

View full text Add to dashboard Cite

Aqueous suspensions of platinum colloidal nanoparticles of varying size and polydispersity have been produced by ablation of a platinum target with a nanosecond Q-switched Nd:YAG laser. Several laser wavelengths (1064, 532 and 266 nm) and stabilizing agents (citrate and polymers PEG, PVA and PVP) were employed. Laser ablation with the infrared and visible wavelengths leads to spherical amorphous nanoparticles with a bimodal distribution of diameters, featuring a global maximum in the range 5-10 nm and a shoulder extending to 25 nm. Such bimodal distributions plausibly arise from thermal and explosive vaporization mechanisms occurring in different time scales, as proposed in earlier studies.Ultraviolet ablation of Pt at 266 nm, reported here for the first time, produces crystalline nanoparticles of small size (1-4 nm diameter), with a weak onset of larger particles (6-8 nm). The ablation at 266 nm also produced an appreciable yield of large rod-like particles of size ∼ 10 x 70 nm 2 , especially in the presence of PEG and PVA. The Pt nanoparticles served to fabricate films capable of assisting the laser desorption ionization (LDI) of a model peptide. The best analytical performance for LDI mass spectrometric detection was obtained with Pt nanoparticles surface functionalized with citrate and PVA.

show abstract

Section: Ablation Process and Nanoparticle Growth Mechanismsmentioning

confidence: 99%

Platinum Nanoparticles as Photoactive Substrates for Mass Spectrometry and Spectroscopy Sensors

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The amplitude and the phase of these thermal waves depend on the thermophysical properties of a specimen, properties of surfaces and interfaces, and the presence of subsurface defects and cracks. There are a number of photothermal techniques for measuring physical properties of materials (for an overview of the photothermal techniques, see [1]), e.g., photothermal displacement spectroscopy [2][3][4][5], photoacoustic spectroscopy [6][7][8], photothermal radiometry [9,10], and the "mirage effect" associated with deflection of the monitoring beam caused by a gradient of the refractive index of air in the vicinity of the heated surface [11,12]. A limitation of the latter method is that the optical characteristics, e.g., absorption coefficient of the heated surface and physical properties of the surrounding air influence the measured parameters of the monitoring beam.…”

Section: Introductionmentioning

confidence: 99%

Theory of Photothermal Displacement Method for Determining Physical Properties of Multilayered Coatings

Elperin

Rudin

2009

Int J Thermophys

View full text Add to dashboard Cite

In this study theoretical principles underlying the photothermal method for determining thermal properties of opaque multilayered and functionally graded coatings are analyzed. The method is based on irradiation of the assembly by the repetitive pulse of focused laser radiation that is absorbed in the subsurface region and causes non-uniform heating and buckling of a coating. The irradiated surface of a coating is monitored by a low power beam of a second laser that is reflected from the specimen. The deflection angle of the monitoring beam, as a function of time, contains the relaxation and the "wave" components. It is shown that the phase of the "wave" component depends on the thermophysical properties (e.g., thermal diffusivity or thermal conductivity) of a coating. These properties can be determined by comparing experimentally measured values of the phase shift of the "wave" component with the theoretical values obtained from the analytical solution of the two-dimensional thermal elasticity problem for a multilayered coating-substrate assembly.

show abstract

“…There are a number of photothermal techniques for the measurement of physical properties of materials, e.g., photothermal displacement spectroscopy [1], photoacoustic spectroscopy, photothermal radiometry [2][3][4][5], and the "mirage effect" [2,6]. These contact-free highly sensitive methods successfully overcome many difficulties inherent in the traditional contact methods.…”

Section: Introductionmentioning

confidence: 99%

“Thermal Mirror” Method for Measuring Physical Properties of Multilayered Coatings

Elperin

Rudin

2007

Int J Thermophys

View full text Add to dashboard Cite

In this study theoretical principles underlying the photothermal displacement ("thermal mirror") method for measuring physical properties of opaque multilayered and functionally graded coatings with low thermal conductivity are analyzed. In this method, the specimen is locally heated by a power laser beam, and a two-dimensional transient temperature field is formed in a specimen. The physical basis for the photothermal displacement method is the non-stationary buckling and displacement of an irradiated surface due to a non-uniform thermal expansion. The surface is monitored by a low-power probe beam of a second laser, which is reflected from the specimen, i.e., the system operates as a convex "thermal mirror." The photoinduced displacement varies with time, and the probe beam is reflected at a different angle depending on the slope of the displacement. The deflection angle is measured as a function of time by a position sensor, and the results of these measurements are compared with the theoretical dependence of the deflection angle on time and physical properties of a coating. This dependence was determined analytically from the solution of the two-dimensional thermal elasticity problem. It is shown that for the specimen composed of a substrate and a coating it is feasible to determine the properties of the coating, e.g., the thermal diffusivity and coefficient of linear thermal expansion provided that the analogous properties of the substrate are previously measured or otherwise known.

show abstract

Untitled

Cited by 11 publications

References 4 publications

Platinum Nanoparticles as Photoactive Substrates for Mass Spectrometry and Spectroscopy Sensors

Platinum Nanoparticles as Photoactive Substrates for Mass Spectrometry and Spectroscopy Sensors

Theory of Photothermal Displacement Method for Determining Physical Properties of Multilayered Coatings

“Thermal Mirror” Method for Measuring Physical Properties of Multilayered Coatings

Contact Info

Product

Resources

About