Thermoplastic Polyurethanes (TPUs) are widely used industrial segmented elastomers composed of a soft segment (SS) that gives the extensibility owing to its low Tg, and a hard segment (HS) that gives toughness. It is well known and sizably argued by many experimental observations that the copolymer design factors such as the SS-HS chemical structure, ratio, size/length distributions and solvents used in synthesis and/or processing of copolymers drastically alter macro-properties of TPUs. On the contrary to these vast amount of knowledge, few researchers focus on micro- or nano-scale events taking place during the changes in observable macro properties of TPUs. Therefore, investigations of structure-morphology-function relationships of TPUs are a still-developing area with many research questions yet to be answered. TPUS are conventionally prepared by varieties of building blocks, but are only synthesized in a limited number of solvents. This study deals with the investigation and explanation of the effect of design parameters such as SS chemistry and solvent system, on final polymer morphology and phase properties of a set of TPUs by Dissipative Particle Dynamics (DPD) simulations. To achieve this, we have first prepared 3D models of TPUs with SS that are frequently found and studied in TPU literature. We have then calculated their Flory-Huggins Interaction Parameters (FHIP) and consequently the DPD parameter to use in coarse graining of 3D polymer models into DPD beads. Finally, we have performed comprehensive DPD simulations of the entire set of TPUs in a range of dual solvent mixture of THF/DMF. Based on FHIP and DPD parameters of SS with solvent employed, we observe 3 clusters of SS; with interactions of moderate, strong and very strong. Following the DPD simulations of these clusters, we obtain various micro-phase formations, i.e. micro-phase separation, channel formation and micro-phase mixing, independent of TPU chemistry. Conformational changes taking place between phases are carefully monitored and the structural indicators causing conformation switches are put forth. Finally, we have supported our findings on micro-phase formations with an expanded version of Integral FHIP (I-FHIP) for the quaternary system of HS, SS, THF and DMF. We have successfully demonstrated that DPD simulations are particularly suitable for predicting the variables of this theory. This study offers two design parameters for TPU synthesis, solvent ratio and SS chemistry, to control micro-phase separation/mixing. The selection method developed in this study enables researchers design novel TPUs with desired morphologies and macroscopic properties.