The effect of temperature/humidity treatment conditions on the interfacial adhesion energy between an electroless-plated Ni film and a polyimide substrate was evaluated by using a 180° peel test. The measured peel strength values decrease from 506.1 ±18.6 to 231.9 ±33.3 J/m2 due to the temperature/humidity treatment at 85 °C/85% relative humidity for 1000 h. X-ray photoelectron spectroscopy analysis of the peeled surfaces indicates that peeling occurs cohesively inside of the polyimide; this is related to both the decrease in the interfacial adhesion energy and the polyimide degradation when small quantities of the remaining alkali ions react with the polyimide's functional groups during the temperature/humidity treatment.

The effects of KOH + ethylenediamine (EDA) and subsequent KMnO 4 + KOH treatments on the interfacial adhesion characteristics of an electroless-plated Ni/polyimide system were investigated for flexible printed circuit board applications. The interfacial adhesion energy, evaluated from 180°peel tests during the steady-state peeling process, showed a twofold decrease after subsequent KMnO 4 + KOH treatment of the pyromellitic dianhydianilineoxydianiline polyimide surface. Atomic force microscopy and x-ray photoemission spectroscopy results clearly reveal that this decrease can be attributed to both mechanical interlocking and chemical bonding effects.

The effect of annealing on the interfacial adhesion energy between electroless-plated Ni films and polyimide substrates was evaluated using a 180-degree peel test. The measured peel strength values decrease from 263.6 ± 7.8 J/m 2 to 109.3 ± 6.4 J/m 2 after annealing for 100 h at 200°C in an ambient environment. XPS analysis on the peeled surfaces reveals that the peeling is due to cohesive failure inside the polyimide, which is related to the fact that wet treatment produces an activated bonding mechanism between electroless-plated Ni and polyimide. This implies a degradation of the polyimide structure due to oxygen diffusion through the interface between Ni and alkali wet-treated polyimide, which is also closely related to the decrease in the interfacial adhesion energy due to thermal treatment in ambient conditions.

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Recent advances in the experimental and theoretical investigation of the excitation of the (np 5 (n + 1)s 2 ) 2 P 3/2,1/2 autoionizing states in alkali atoms is reported. These include a joint theoretical and experimental investigation of the lowest (5p 5 6s 2 ) 2 P 3/2 autoionizing state in Cs, for which the ejected-electron excitation function was measured at an incident-electron energy resolution of 0.2 eV for impact energies up to 4 eV above the threshold, an improved R-matrix calculation for electron-impact excitation of the (3p 5 4s 2 ) 2 P 3/2,1/2 leading autoionizing doublet in K, and a theoretical study of the inner-shell photodetachment of the Na − ion. The calculations for sodium and potassium were performed by employing a B-spline R-matrix (close-coupling) code in the semi-relativistic Breit-Pauli approximation, whereas the calculations for caesium were carried out with a new fully relativistic Dirac B-spline R-matrix program. All excitation functions reveal pronounced near-threshold resonance features, which were analysed and tentatively assigned on the basis of the present calculations.