The international entrepreneurial firm's social networks

This paper investigates theoretically the importance and impact of the international entrepreneurial firms’ (IEFs) social networks on selected firms’ strategies. We focus specifically on some core attributes of IEFs and the impact of social networks on such strategies as the choice of the foreign markets to operate and the foreign entry modes. The social networks are a major driver of the internationalization from inception and help in overcoming a variety of physical and social resource limitations as well as transactional hazards. We conclude that it is likely that both some fundamental characteristics of the IEFs and those of the foreign markets entered account for these firms reliance on their social networks

Ion transport across membranes prepared by gel crystallization

A one-step procedure for the preparation of ion-selective membranes is described. The method employs the thermally induced gel crystallization of ultrahigh molecular weight poly(ethylene) (UHMW-PE) from a dilute xylene solution. After evaporation of the xylene, a microporous UHMW-PE film remains, which can serve as the support for liquid and polymeric ion-selective membranes. The addition of a membrane solvent and suitable receptor molecules to the xylene solution allows a one-step incorporation of these membrane components into the UHMW-PE support. The influence of the preparation conditions of the UHMW-PE support on the rates of the p-tert-butylcalix[4]arene tetraethylester-mediated transport of NaClO₄ was studied. Two concepts to improve the life-time of the membranes are introduced. In a first approach, the addition of photocrosslinkable nitril-substituted siloxane copolymers to the membrane phase has been evaluated. The enhanced viscosity of the membrane phase reduces leaching of carrier and solvent molecules from the membrane into the aqueous phases. In a second approach, the solvent is omitted and the membrane-phase merely consists of a benzo-15-crown-5 or calix[4]arene modified siloxane-copolymer, which is substituted to such a degree that ion transport no longer has to take place via diffusion of host-guest complexes but by jumping of the cations from one fixed carrier to a neighboring carrie