3D printing technologies have been widely used for the rapid prototyping of 3D structures, but their application in a broader context has been hampered by their low printing throughput. For the same structures to be produced in a variety of sizes and materials, each must be printed separately, which increases time and cost. Replicating 3D-printed structures in a variety of sizes using a molding process with size-tunable molds could be a solution, but it has only been applied to simple structures, such as those with tapered or vertical profiles. This work demonstrates the generation of multiple replicas of varying sizes and materials from a single 3D-printed template with complex geometries by using molds made of stretchable hydrogel that shrink isotropically. We optimize hydrogel compositions to synthesize a hydrogel that is highly stretchable and shrinks isotropically in all directions. The high stretchability of this hydrogel allows for the removal of complex 3D-printed templates from hydrogel molds. The cavities of the hydrogel molds are then filled with polycaprolactone (PCL) and dried at 80 °C. As the hydrogel shrinks due to drying, the melted PCL fragments completely fill the cavities. The entire process can be repeated to produce multiple replicas in a variety of sizes and materials. Replicas that are one-tenth of the size of the original printed template can be produced. Finally, we demonstrate how our method can be used to reduce the size of interconnected geometries, which would be impossible to achieve using traditional molding processes.
This paper describes the use of the layered conductive metal-organic framework (MOF) (nickel)-(hexahydroxytriphenylene) [Ni(HHTP)] as a model system for understanding the process of self-assembly within this class of materials. We confirm and quantify experimentally the role of the oxidant in the synthetic process. Monitoring the deposition of Ni(HHTP) with infrared spectroscopy revealed that MOF formation is characterized by an initial induction period, followed by linear growth with respect to time.
Hyperspectral (HS) imaging bridges conventional imaging into spectroscopy and generates a spatial map of spectral variations. On the one hand, in HS imaging, the effect of the background on the final spectra has to be removed or managed. On the other hand, there are important classes of materials that need to be immobilized for investigation.
Well-constructed instruments may continue to perform beyond their manufacturer-supported service lifetime, which is typically limited by computer operating system compatibility or the availability of spare parts. Often, such equipment is condemned to surplus and destroyed. End-of-life plans that retain some of the material and energy used to create scientific instruments are of interest, just as in other manufacturing sectors.
This paper addresses the trade-off between sensitivity and sensing range in strain sensors, while introducing additional functionalities through an innovative 4D printing approach. The resulting ultraflexible sensor integrates carbon nanotubes/liquid metal hybrids and iron powders within an Ecoflex matrix. The optimization of this composition enables the creation of an uncured resin ideal for Direct Ink Writing (DIW) and a cured sensor with exceptional electromechanical, thermal, and magnetic performance.
Introduction: Silver sulfadiazine 1 % cream had historically been the mainstay initial treatment for scald wounds at our institution. However, we transitioned to using closed dressings of only petrolatum-impregnated 3 % bismuth tribromophenate gauze (Xeroform) for all partial-thickness burns. Xeroform adheres to the wound while allowing the exudates to drain and acts as a scaffold for re-epithelialization, after which it falls off without traumatizing the wound bed, theoretically allowing viable tissue to declare itself while requiring less frequent dressing changes.
