Facile and Scalable Fabrication of Flexible Reattachable Ionomer Nanopatterns by Continuous Multidimensional Nanoinscribing and Low-temperature Roll Imprinting

Abstract

We develop a facile route to the scalable fabrication of flexible reattachable ionomer nanopatterns (RAINs) by continuous nanoinscribing and low-temperature roll imprinting, which are repeatedly attachable to and detachable from arbitrarily shaped surfaces. First, by sequentially performing continuous nanoinscribing over a polymer substrate along the multiple directions, we readily create the multidimensional nanopattern, which otherwise demands complex nanofabrication. After its transfer to an elastomer pad for use as a soft nanoimprinting stamp, we then conduct a low-temperature roll imprinting of the ionomer film to fabricate a flexible and highly transparent RAIN. Reversible loosening of ionic units in the ionomer material at the mild temperature as low as ∼60−70 °C enables the faithful nanopatterning over thermosensitive organic compounds and fragile materials under a slight pressure. The excellent adhesion purely emerging from ionic interactions uniquely realizes the conformal attachability and clean detachability of RAINs for universal targets in ambient conditions, particularly beneficial for individual wearable and mobile devices requiring the userspecific "on/off" of the nanopattern-driven functionalities. As one vivid example, we demonstrate that a single light-emitting device can be switched from the focused pointer to the widespread flashlight depending on the RAIN application upon user's purpose.

Scalable and High-Throughput Top-Down Manufacturing of Optical Metasurfaces

“…With the advantages of both DNI and VIP methods such as the compact and vacuum-free system, it is competitive imprint method for precise machining for optical applications [145,188]. For example, Oh et al developed flexible reattachable ionomer nonpatterns (RAINs) with DNI and low-temperature roll imprinting [189]. They can be fabricated under reasonable temperatures as low as 60-70 • C, so can therefore be used for thermosensitive products such as organic light emitting diodes (OLED).…”

Size-Selective Sub-micrometer-Particle Confinement Utilizing Ionic Entropy-Directed Trapping in Inscribed Nanovoid Patterns

“…39,41 The DNI strokes can be sequentially repeated in the orthogonal direction to produce the 2D sinusoidal nanovoid pattern (Figure 1d). 38,40 In DNI, the pattern period is dictated by that of the grating mold, and thus nanovoids of specific sizes (i.e., depending on the target particles to selectively catch) can be precisely created by 2D-DNI in a continuous and scalable fashion at high speed (∼1 m/min or faster), which is not available by other conventional techniques. For instance, we used a 700 nm period SiO 2 grating mold for the 700 nm diameter nanovoid patterning on polycarbonate (PC) substrates in this work (unless otherwise noted).…”

“…Fabrication of the microscale well arrays as particle-trapping templates through conventional nanofabrication approach has been demanding and often of poor reproducibility due to complex mask design, tricky etching, and limited area . However, a high-throughput and scalable fabrication of the nanovoid patterns could be implemented by using two-dimensional dynamic nanoinscribing (2D-DNI) comprised of sequential continuous mechanical inscribing strokes. − By exploiting geometry-induced electrostatic interaction − between charged particles and the nanovoid array in ionic solution, we achieved topography-directed, position-selective localization of particles, arranging particles at positions that are predefined by the nanovoid topography and surface charge, instead of randomly depositing them on the substrate. We further elucidate that the "well" depth of the total free energy is contributed by the ionic entropy as well as the electrostatic potential between a particle and void surface.…”

Solution-processable electrode-material embedding in dynamically inscribed nanopatterns (SPEEDIN) for continuous fabrication of durable flexible devices

“…The polymer substrates (PC; DE 1-1, CLEAR, Makrofol; PI; HN 1 mil, Kapton) were thoroughly cleaned by isopropyl alcohol (IPA) and deionized water and dried by nitrogen blowing before use. The detailed design, setup, and operation of a custom-built DNI processing system for the fabrication of 1D-and 2D-micro-and nanopatterns are described elsewhere 38,41,46 . Briefly, the ridge mold edge was mounted on a heater-attached arm and brought to a conformal contact with the substrate with a typical tilting angle of 35-40°.…”

“…In these regards, a more productive and scalable methodology is needed for a facile and cost-effective fabrication of more durable MNPs on desirable flexible substrates [38][39][40][41] . More specifically, the proposed method may realize photomask-and etch-free micro-and nanopatterning and vacuum-free metalizing therein at a low temperature [42][43][44][45] .…”