Flexible fluid-based encapsulation platform for water-sensitive materials

Abstract

The next-generation semiconductors and devices, such as halide perovskites and flexible electronics, are extremely sensitive to water, thus demanding highly effective protection that not only seals out water in all forms (vapor, droplet, and ice), but simultaneously provides mechanical flexibility, durability, transparency, and self-cleaning. Although various solid-state encapsulation methods have been developed, no strategy is available that can fully meet all the above requirements. Here, we report a bioinspired liquid-based encapsulation strategy that offers protection from water without sacrificing the operational properties of the encapsulated materials. Using halide perovskite as a model system, we show that damage to the perovskite from exposure to water is drastically reduced when it is coated by a polymer matrix with infused hydrophobic oil. With a combination of experimental and simulation studies, we elucidated the fundamental transport mechanisms of ultralow water transmission rate that stem from the ability of the infused liquid to fill-in and reduce defects in the coating layer, thus eliminating the low-energy diffusion pathways, and to cause water molecules to diffuse as clusters, which act together as an excellent water permeation barrier. Importantly, the presence of the liquid, as the central component in this encapsulation method provides a unique possibility of reversing the water transport direction; therefore, the lifetime of enclosed water-sensitive materials could be significantly extended via replenishing the hydrophobic oils regularly. We show that the liquid encapsulation platform presented here has high potential in providing not only water protection of the functional device but also flexibility, optical transparency, and self-healing of the coating layer, which are critical for a variety of applications, such as in perovskite solar cells and bioelectronics.

Soft mechanical sensors for wearable and implantable applications

“…In addition to high conformability and low vapor permeability, such encapsulation must also be biocompatible and have minimal interference on the encapsulated sensor's sensing capabilities and mechanical properties. Recent progress has been made in the employment of different soft materials, such as liquid metals (Shen et al, 2023) and lubricant-infused polymers (Lemaire et al, 2023), in the fabrication of mechanically compliant encapsulation layers, providing potential research directions for the development of highly robust encapsulation of soft mechanical sensors in wearable and implantable settings. 5.…”

“…In addition to high conformability and low vapor permeability, such encapsulation must also be biocompatible and have minimal interference on the encapsulated sensor's sensing capabilities and mechanical properties. Recent progress has been made in the employment of different soft materials, such as liquid metals (Shen et al, 2023) and lubricant‐infused polymers (Lemaire et al, 2023), in the fabrication of mechanically compliant encapsulation layers, providing potential research directions for the development of highly robust encapsulation of soft mechanical sensors in wearable and implantable settings. Large‐scale manufacturing with low device‐to‐device variation: In order to realize commercial and clinical viability, further advancements in the use of scalable manufacturing techniques to fabricate soft mechanical sensors are necessary. While techniques such as inkjet printing and photolithography have already been used to fabricate sensors in a highly scalable way (as discussed in Section 3.7), further exploration of large‐scale manufacturing techniques for a broader range of materials that can enable the different aforementioned human‐compatible properties is required.…”

Fully Biodegradable Packaging Films for Fresh Food Storage Based on Oil‐Infused Bacterial Cellulose

“…The OBC was prepared according to a previous liquid‐solid composite method. [ 57 ] The oil was a mixture of 20 mL palm oil, 20 mL thyme essential oil, and 4 mL cinnamaldehyde (i.e., the volume ratio of palm oil: thyme essential oil: cinnamaldehyde was 5:5:1). Prior to the infusion, the oil mixture was stirred in a conical flask for 2 h at a speed of 500 r min −1 .…”