Quantitative depth profiles from polymer surfaces by angle-resolved X-ray photoelectron spectroscopy

Surfaces ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 352-365
Author(s):  
Javier Mateo Moreno ◽  
Rodrigo Calvo Membibre ◽  
Sergio Pinilla Yanguas ◽  
Juan Rubio Zuazo ◽  
Miguel Manso Siván

The formation of xerogels implies a sequence of hydrolysis and condensation reactions, which are intricate to analyze in heteromolecular sols. We analyze by probabilistic Montecarlo methods the development of hybrid organosilane–titania xerogels and illustrate how partial charges of the reacting molecules can help estimating relative probabilities for the condensation of the molecules. Since the condensation rate of Ti alkoxides is much higher than the corresponding rate of Si alkoxides (especially if bearing a non-hydrolizable group), by imposing a fast condensation process in agreement with low pH kinetics, the process leads to a surface segregation of the organosilane. The simulation results are compared with results of characterization of thin condensates of two different organosilanes within a titanium–isopropoxide matrix. Non-destructive in-depth profiles were obtained by hard x-ray photoelectron spectroscopy, which can resolve through estimation of Si and specific moieties of the organosilane molecules the progress of the condensation. These results are relevant for the generalization of chemo-functionalization processes by kinetic demixing of organosilanes, which have myriad applications in biomedicine and biotechnology.


1995 ◽  
Vol 385 ◽  
Author(s):  
Stefan Lätsch ◽  
Hiroyuki Hiraoka ◽  
Joachim Bargon

ABSTRACTCu, Ni, and Au were deposited with defined patterns and good adhesion by electroless plating, e-beam evaporation, and sputtering onto Teflon (polytetrafluoroethylene, PTFE), Teflon ET (PTFE-co-ethylene), Teflon FEP (PTFE-co-hexafluoropropylene) and Teflon PFA (PTFE-coperfluoroalkoxy vinyl ether) surfaces. The polymers had been irradiated in a tetramethyl – ammonium hydoxide solution (TMAH) by a Nd:YAG laser at 266 rim and by an excimer laser at 248 nrm prior to the metal deposition process. Both, the treated and virgin polymer surfaces were characterized by x-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS) and Micro-Raman spectroscopy. The increased metal to polymer adhesion at the interface was found to be due to chemical changes and is in the order Ni > Cu ≅ Au.


2001 ◽  
Vol 690 ◽  
Author(s):  
Jay H. Lee ◽  
Hee D. Jeong ◽  
Il C. Rho ◽  
Chong S. Yoon ◽  
Chang K. Kim

ABSTRACTExtent of Mn diffusion to the plasma-oxidized AlOx tunnel barrier of magnetic tunnel junction was examined using Auger Electron Spectroscopy (AES) and X-Ray Photoelectron Spectroscopy (XPS). A magnetic film stack consisting of Ta/AlOx/CoFe/IrMn/NiFe/Ta was deposited with the AlOx layer treated under different plasma oxidation durations. AES depth profiles showed that Mn diffusion to the AlOx/CoFe interface increased with increasing oxidation after annealing at 300°C. XPS analysis indicated that Mn found at the CoFe/AlOx interface in the over-oxidized electrode was in the form of MnO2. Our research suggests that Mn diffusion was accelerated by preferential oxidation of Mn at the CoFe/AlOx interface.


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