Rapid assembly of multilayer microfluidic structures via 3D-printed transfer molding and bonding

Abstract

A critical feature of state-of-the-art microfluidic technologies is the ability to fabricate multilayer structures without relying on the expensive equipment and facilities required by soft lithography-defined processes. Here, three-dimensional (3D) printed polymer molds are used to construct multilayer poly(dimethylsiloxane) (PDMS) devices by employing unique molding, bonding, alignment, and rapid assembly processes. Specifically, a novel single-layer, two-sided molding method is developed to realize two channel levels, non-planar membranes/valves, vertical interconnects (vias) between channel levels, and integrated inlet/outlet ports for fast linkages to external fluidic systems. As a demonstration, a single-layer membrane microvalve is constructed and tested by applying various gate pressures under parametric variation of source pressure, illustrating a high degree of flow rate control. In addition, multilayer structures are fabricated through an intralayer bonding procedure that uses custom 3D-printed stamps to selectively apply uncured liquid PDMS adhesive only to bonding interfaces without clogging fluidic channels. Using integrated alignment marks to accurately position both stamps and individual layers, this technique is demonstrated by rapidly assembling a six-layer microfluidic device. By combining the versatility of 3D printing while retaining the favorable mechanical and biological properties of PDMS, this work can potentially open up a new class of manufacturing techniques for multilayer microfluidic systems.

Flexible Shear and Normal Force Sensor Using only One Layer of Polyvinylidene Fluoride Film

“…The fabrication process of the sensor is shown in Figure 1a-c. First, two custom-made molds were fabricated with a 3D printer (ProJet HD3500 Plus, 3D Systems, Inc.) in ultra-high-definition (UHD) mode using VisiJet M3 Crystal and VisiJet S300 as the build and support materials, respectively. Then, the molds were coated with trichlorosilane (Sigma Aldrich, Inc.) to easily separate the PDMS from these molds [36]. PDMS (SYLGARD 184 A/B, Dow Corning Corp.) was molded using the custom-made molds and cured at 55 • C for 4 h to fabricate the bottom and top PDMS ( Figure 1a).…”

Use DNA origami as a scaffold for self-assembly of optical metamolecules

“…The microfluidic top-plane would require at least two distinct PDMS layers, which is possible using conventional casting and bonding, 9 or 3D-printing methods. 24 Hence the final device structure (Fig. 1f) would be: (from bottom) CMOS backplane, 8 thin glass floor, 8 PMMA nanochannel layer, 7 polycarbonate membrane, 5 and microfluidics layers.…”

3D‐printed polymer packing structures: Uniformity of morphology and mechanical properties via microprocessing conditions

“…However, 3D printing is a layer-by-layer process; as a result, the different crystallization conditions experienced by the part is nonuniform, resulting in nonuniform surfaces and mismatched joints. [11,12] For a printed part intended for use as a food container or skin-contacting device, the surface roughness is exceedingly important for the safety and comfort of the user. In addition, the packing materials must have proper mechanical properties to ensure their durability and longevity.…”