Effect of molds on curing in pdms fabrication and deformation in pdms based microfluidic chips

Official URL: https://risc01.sabanciuniv.edu/record=b3402102

In this thesis, two different approaches on polydimethylsiloxane(PDMS) curing and deformation in microfluidic chips were discussed. PDMS is the most preferred microfluidic chip raw material since it allows easy and cheap fabrication of microfluidic chips compared to other production methods. Biocompability, flexibility and easy fabrication of microfluidic chips make PDMS popular material, especially for biotechnological applications such as organ-a-chip devices. Recently, 3D printing has become a popular alternative method in PDMS mold fabrication because it is easy and practical. A wide variety of materials has been used in 3D printing, and it was observed that these materials affect the PDMS curing. The first part of this study examines the effect of molds with the same dimensions, which were fabricated using four different materials, on PDMS curing. The findings indicate that the choice of mold material affects both the curing kinetics of PDMS and consequently, the mechanical properties of the material. However, this influence is not substantial in the overall efficiency of curing at the selected temperatures and curing duration. PDMS based microfluidic chips deform under the influence of the liquid flowing through microfluidic channels especially near the channel inlet where the pressure is the highest. This change is due to the elasticiy of PDMS. In the second part of the thesis, the deformations in microfluidic chips with different dimensions and curing patterns were analyzed. The findings indicate that at low flow rates, the deformation ratio of microchannels with identical dimensions is notably influenced by elasticity. However, as the flow rate in creases, the impact of elasticity diminishes.