Mössbauer Study of Tin(II) Sensitizer Deposits on Kapton

Abstract

Mössbauer spectroscopy has been used to study tin(II) sensitizer deposits formed on Kapton films (du Pont polyimide) for use in the recently reported photoselective metal deposition (PSMD) process. Combined with previous results, this work shows that the sensitizer is present as a colloid in the sensitizing bath and is adsorbed on the substrate when it is dipped. This activation mechanism would be expected to apply to other insulating substrates as well. The photosensitive substance contains more tetravalent tin than divalent. The divalent tin is oxidized by exposure either to air or to the Pd activation bath. The photosensitive compound is not any well recognized tin oxychloride or hydroxide.

Reductive spectrophotometry of divalent tin sensitization on soda lime glass

“…In contrast with reductive spectroscopy, use of radioactive isotopes incurs processing delays as well as regulatory and safety concerns: sensitized samples containing traces of Sn 113 atoms required 24 h storage to allow ingrowth of indium isotope daughter In 113m and decay of any co-deposited In 113m before recording its activity [24]. For Kapton films sensitized with SnCl 2 ·2H 2 O (∼45 mM), Mossbauer spectroscopy was used to measure tin (II)/tin (IV) ratio of 1:2, which was within the range of tin (II)/tin (IV) ratios found in this study [26]. For alumina substrates, X-ray fluorescent spectrometry was used to measure 1.16 nmol/cm 2 of total tin [27].…”

“…As with Rutherford backscattering, X-ray fluorescence successfully quantitated total tin content but did not distinguish tin (II) from tin (IV) [21,23,27]. Mossbauer and radiochemical tracer analysis could distinguish elemental states of tin, but have not been used for rapid, in situ quantitation of tin, as in the present study [24][25][26].…”

“…But they have not been applied to quantitate the mass of tin (II) deposited on substrates to sensitize EL plating. The effects of tin sensitization, and activation steps on EL plating along with substrate properties have been evaluated by Rutherford backscattering [21][22][23], radiochemical tracer analysis [24,25], Mossbauer spectroscopy [26], X-ray fluorescence spectrometry [27] and X-ray photoelectron spectroscopy (XPS) [28]. Challenges of these methods [13,29] underscore a need for rapid, in situ evaluation of tin (II) deposited during sensitization with respect to operational variables, e.g., sensitization time, analyte concentration, aqueous immersion, and acid content.…”

Selective Metal Pattern Fabrication Through Micro-Contact or Ink-Jet Printing and Electroless Plating onto Polymer Surfaces Chemically Modified by Plasma Treatments

“…Surface activation can then be performed using two main processes known as ''two-step'' or ''one-step'' processes. In the former case [27][28][29][30], the oxidized substrate surface is first sensitized by immersion in an acidic tin chloride (SnCl 2 ) solution and then activated by immersion in an acidic palladium 692 F. Bessueille et al…”

Chemotactic Receptors of Dictyostelium discoideum

“…From extensive time lapse cinematographic studies of aggregating cells, Robertson and coworkers [33] and others [12] have been forced to postulate a refractory period during which the cells which have just responded to the chemotactic signal remain unresponsive for a period of about 1 to 5 min duration. This seems necessary to account for the fact that cells which have moved toward a center do not move in an outward direction when the immediately outlying cells secrete cAMP in response to the propagated stimulus [33]. However,it has been impossible to detect such a refractory period in cell movement using direct stimulation of cells with a micropipette loaded with CAMP [23].…”