Fabrication of Patterned Concave Microstructures by Inkjet Imprinting

Abstract

Concave microstructures such as microwells and microgrooves are widely utilized in fields such as biochips, microfluidics, and functional devices. Previously, concave microstructure fabrication was mostly based on laser etching or lithography which is either costly or of multisteps. The inkjet etching method is a direct structuring technique, but limited by its inherent transverse ink diffusion that leads to low feature resolution. Nanoimprint lithography can reach submicro and even nano ranges, whereas an elaborate template is needed. Thus, it is still a challenge to realize controllable fabrication of concave microstructures in large areas with high efficiency and resolution. Here, a template‐free strategy to fabricate concave microstructures with high resolution by inkjet imprinting is provided. In this method, a sacrificial ink is inkjet‐printed onto a precured viscoelastic surface and imprints its shapes to construct concave microstructures. The morphology of the microstructures could be adjusted by controlling the interaction between the two immiscible phases. The microwells/microgrooves could be used to pattern single cells and functional materials such as optical, electronic, and magnetic nanoparticles. These results will open a new pathway to fabricate concave microstructures and broaden their applications in various functional devices.

Fabrication of Transparent Multilayer Circuits by Inkjet Printing

“…Besides, the high viscosity and low surface energy of liquid PDMS precursor have been utilized to fabricate microfluidic and other functional devices. [17a,20] Here, we demonstrate that the liquid PDMS precursor substrate could be used to inkjet print high‐resolution embedded microcables. Silver nanoparticles (AgNPs) suspension was used as the conductive ink due to its high conductivity and widespread application in printed electronics .…”

Pyro-EHD ink-jet printing for direct functionalization of 3D lab-on-chip devices

“…Once a thermal gradient is applied it causes the pyroelectric effect, namely a change in P s as a function of temperature leading to an excess or lack of screening charges on the LN surface. Such uncompensated charge's density, ρ = Δ (P s -σ sc ), generates a high electric field as large as 10 6 -10 8 V/cm 19,20 . The relationship between the change in temperature and the change in spontaneous polarization is linear and can be written as ΔP i = p i ΔT, where P i is the coefficient of the polarization vector, p i is the pyroelectric coefficient (-4 × 10 -5 C/(m 2 K)), and ΔT is the temperature variation.…”

Conductive Hydrogels as Smart Materials for Flexible Electronic Devices

“…However, owing to the difficulties in developing stretchable electric materials, the main strategy in attempting to achieve stretchability is not to develop new materials, but engineer new structural constructs from exiting materials. For example, net‐shaped, ripple‐like, and spring‐like circuits were designed to meet the flexible demand . However, these sensors need to fabricate complicated microstructures and nanostructures and require the rigorous experimental instruments and operation.…”

“…For example, net-shaped, ripple-like, and spring-like circuits wered esigned to meet the flexible demand. [135][136][137][138][139] However,t hese sensorsn eed to fabricate complicated microstructures and nanostructures and require the rigorous experimental instruments and operation. Conductive hydrogel materials show attractivea dvantages in improving the rigid of flexible sensors as wella si ntroducing new approaches for sensing sensors manufacturing.…”