| Recently, researchers from Pennsylvania State University have successfully used the PDMS elastomeric mixture to 3D complex geometry printing, a variety of common silicon-based organic polymers. The 3D printed PDMS has excellent tensile strength and can be used to mold or cast PDMS .  In general, the biggest advantage of 3D printing as opposed to casting and molding is that complex shapes can be achieved, such as forming objects with complex internal and external geometries that can not be created by pouring liquid material into a mold copy. However, by making some adjustments to the additive manufacturing process, 3D printed parts made from a given material can be more robust than conventionally manufactured parts made from the same material.A team of researchers at Pennsylvania State University is seeking to optimize A similar success has just been achieved with 3D-printed PDMS (polydimethylsiloxane or silicone) by combining two PDMS elastomers to improve mechanical properties and better bioadhesion. PDMS is still the most common product used to make chip-like lab equipment and 3D cell culture platforms, etc. Kitchenware such as heat-resistant silicone squeegees, etc. However, while simple-shaped objects such as spatulas can be made with molding equipment, sometimes Small objects such as lab-on-a-chip devices require more subtle manufacturing methods. There are other shortcomings in molding or casting PDMS, and according to Ibrahim T. Ozbolat, associate professor of engineering sciences and mechanics and bioengineering at Penn State University, casting or micromachining results in weaker mechanical properties and weaker cell adhesion. This means that researchers often use extracellular proteins such as fibronectin to attach cells. But that does not mean that engineers should turn to 3D printing to handle their PDMS because the material does not always have the proper extrusion properties such as PDMS elastomer, Sylgard 184, which is not sticky in 3D printing: it resembles water The same out of the nozzle to form a puddle. So how do you make it 3D printing? By mixing Sylgard 184 with another PDMS elastomer, the SE 1700, researchers at Pennsylvania State University are able to make 3D mixtures of blends that exploit the material's shear-thinning properties to reduce viscosity under shear strain. Ozbolat said : 'We optimized the printability to control the extrusion and fidelity of the original printed pattern.' Materials that show shear thinning are very good for 3D printing because their viscosity fluctuations fit right into the 3D printing device: the material is sufficiently viscous that it can sit in the nozzle without dripping like water, but Can be neatly squeezed out of the nozzle when pressure is applied, and on the outside it becomes more viscous, turning it into a complex shape without collapse.Most materials behave in the opposite way and when subjected to shear pressure Become more viscous. Researchers at Pennsylvania State University are not only making PDMS printable, but they also want to test the bioadhesion of printed materials to see if they can be used in biological applications such as cell culture, etc. In general, this is not the case because molding PDMS has a smooth surface and is also hydrophobic, making it harder to make a harder cell material, but using 3D printed PDMS structures allows researchers to create matte cracks that are ideal for cell use. The bioadhesion test involves the use of a 3D model obtained from the National Institutes of Health in 3D printing on various body parts including human's nose.The nose can be 3D printed without a support structure and includes a hollow cavity. The researchers examined their 3D printed nose with MRI scanners and found the structure to be accurate with almost no deformities thanks to micron-sized needles used in 3D printers to remove any air bubbles in the adhesive material. The 3D printed PDMS nose also shows useful mechanical properties. "Ozbolat said: 'When we compared the mechanical characteristics of PDMS and 3D printed PDMS, we found that the tensile strength of the printed material was much better. For the conclusion, it is believed that the user has guessed that printed PDMS can be stronger than molded PDMS and can be used in biological applications, functional devices made of conductive materials, and multi-material structures.In addition, other researchers participating in the project Including Veli Ozbolat, Madhuri Dey, Bugra Ayan, Adomas Povilianskas and Melik C. Demirel. |
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