Model amphiphilic polymer co-networks (ACNs) are tailor-made adaptive soft solids of covalently crosslinked polymers with both hydrophilic and hydrophobic units. Based on their amphiphilicity, ACNs swell independently in water as well as in organic solvents. The resulting environmentally-sensitive viscoelasticity and selective permeability make them suitable for deliberately controlling the transport of molecules of different polarity through the swollen polymer network (gel). The latter is exploited for soft contact lenses with extended wear time, the most common application of ACNs. Further, biomedical applications are (multi) stimuliresponsive functionalized ACN-based matrices or membranes especially for drug delivery devices , but also for tissue engineering and bioartificial pancreas. In addition, potential technological uses of ACNs are being explored as biocatalyst supports, sensors, and polymer electrolytes for batteries. The properties for all these and other applications are controlled by the polymer network structure, which in turn is strongly dependent on the formation process. A very good overview on the synthesis of ACNs is provided in the review by Erdodi and Kennedy. A major concern of some authors cited there was to obtain networks with defined structure. Although very promising results were achieved in some cases, the attained structures did not comply the criteria of a model network, which is characterized by a homogenous structure of defined length and number of monodisperse polymer strands connected together by junction points of known and constant functionality within an infinite three-dimensional net structure. A seminal paper published by Sakai et al. in 2008 showed one possible way to obtain hydrophilic star-polymer networks with model network structure. Their approach is based on an end-linking process through a hetero-complementary conversion of two four-arm polyethylene glycol stars (A4-and B4-type tetra-PEG) containing different reactive end groups. For star polymers with narrow polydispersity, the number of chain segments between the network junctions is well-fined. Furthermore, the hetero-complementary conversion of the terminal groups avoids that arms of one star react with each other. This eliminates the formation of a significant part of undesirable microscopic defects, leading to a substantial enhancement of the elastic modulus of the networks when prepared at a low overlap number of the network strands. Gels synthesized in this way are characterized by excellent mechanical stability and homogeneity. The structure of such gels is quite close to that of a model network, but still structural defects, like pending arms and double or multiple links between the star polymers develop due to the statistical nature of the cross-linking process. In particular, double links with adjacent stars (see Scheme 1) can be detected and quantified by low-field 1 H multiple-quantum nuclear magnetic resonance (MQ NMR) spectroscopy and Monte-Carlo simulations, which provides detailed insight into the topology of the networks. In recent years, synthesis and characterization of networks with well-defined structures have raised the understanding of their structure-property relations to a new level. In contrast, corresponding studies on amphiphilic co-networks have been performed only sporadically to date. With our contribution, we aim to advance the state of knowledge regarding structure-property relationships of model amphiphilic co-networks.