Solid polymer electrolyte membranes are prepared as semi-interpenetrating networks (semi-IPN) by solution casting technique composed of poly(methyl methacrylate) (PMMA) as polymeric host Matrix, polysiloxane-combpropyloxymethoxytriglycol (PSx) as ion conducting component and lithium bis(trifluoromethane)sulfonimide (LiTFSI) as conducting salt. The resulting semi-IPN (net-poly(methyl methacrylate))-sipn-(polysiloxane-combpropyloxymethoxytriglycol), is investigated using differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and impedance spectroscopy (IS). DSC measurements show two glass transitions (Tg-PSx, Tg-PMMA) indicating an independent coexistence of the PMMA host matrix and the PSx conducting component. FTIR spectroscopy reveals interactions between Li+ ions and the ether-functionality of PSx, whereas PMMA does not interact with the Li+. In order to distinguish PMMA and PSx contributions to the ionic transport, the effective ionic conductivity of PSx was calculated. The ionic conductivity of the semi-IPN is 3.1 x 10(-6) S cm(-1) at room temperature. (C) 2015 Elsevier BM. All rights reserved.