Advanced Materials Technologies最新文献

H₂ Gas Detection

In article number 2302081, Mikhael Bechelany, Lionel Santinacci, Hyoun Woo Kim, Sang Sub Kim, and co-workers describe the development of a highly sensitive and selective H₂ gas sensor. This sensor utilizes ZnO nanowires (NWs) decorated with Pd nanoparticles (NPs) and a NiO shell layer, all deposited via atomic layer deposition. This sensor demonstrates high sensitivity and selectivity to H₂ gas even in the presence of H₂/CO and H₂/NO₂ gasmixtures, offering potential for highly selective H₂ gas detection.

Gold Nanostructured Arrays

In article number 2400019, Qian Zhao, Weiping Cai, and co-workers fabricate a variety of gold nanostructured arrays based on a bowl-shaped tin oxide secondary template with fine structure on its bowl edges, including ‘graphene-structured’ nanoarrays, non-contact nanoparticle ring arrays, closely-contacted nanoring arrays and bowl/nanoparticle binary composite nanoarrays, achieving structural diversity and morphologicalmodifiability. These nanoarrays exhibit structure-induced hydrophilic-hydrophobic transition and a target molecular trapping effect.

Ferroelectric Programmability

In article number 2301562, Osama R. Bilal and Mohamed Roshdy harness electric poling of ferroelectric polymers to program the local stiffness of their metamaterials in a pixelwise fashion. The programmed path can have dynamical properties that are different from the surrounding pixels. The programming can reverse the metamaterials' behavior from attenuating waves to propagating them and vice-versa. These findings advance the applications of elastic waves tunning and control in metamaterials.

Dead Lithium Growth

In article number 2301902, Michel Armand, Andrea Paolella, and co-workers plan-view monitor the nucleation and growth of dendritic and dead Li using a novel anode-free coin cell set-up equipped with a transparent optical window. Operando optical microscopy and computer vision calculations are synergistically combined to observe the evolution of Li metal from a mossy morphology to needle aggregates at low currents, whereas hollow structures are detected at high currents.

Transfer printing is an important material heterogeneous technique with unique capability for developing existing and envisioned electronic or optoelectronic systems. Here, a simple design of ultrasonic droplet stamp is reported featuring a water droplet on an acoustic resonator attached to a glass sheet, for developing an efficient non-contact transfer printing. The water droplet offers the benefits of a gentle and conformal contact, yielding an enough adhesion for a reliable pickup in the absence of ultrasound, and ejects a sub-droplet rapidly due to the Raleigh instability with the ultrasound for an easy non-contact printing. Experimental studies are carried out to investigate the transient response of ultrasonic droplet stamp under the action of ultrasound and showed that the proposed stamp exhibited extraordinary capabilities of damage-free pickup and receiver-independent printing. Demonstrations of the ultrasonic droplet stamp in transfer printing of thin inks with different materials and shapes onto various flat, curved and rough surfaces illustrate its great potential for heterogeneous integration and deterministic assembly.

Ballistocardiography (BCG) studies ballistic forces on the body generated during a heartbeat. As it is an unobtrusive detection method, that requires sensors measuring small dynamic forces. Piezoelectric sensors are ideal, but improvements in sensitivity are needed. Here, a universal method is demonstrated to obtain enhanced effective transverse charge constants by utilizing thin and long sensors fabricated upon compliant substrates. This approach is validated using the uniquely printable and patternable piezoelectric polymer, poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE). Discrete sensors detect displacements of less than 1 µm, dynamic forces of ∼mN, and accelerations of ≈1 mm⁻¹ s². Since the sensor is screen-printable, it is upscaled to a human-sized array (60 × 90 cm, 255 sensors). High quality spatially resolved BCG measurements of a person is demonstrated in seated and supine positions. The obtained heart rate is verified using photoplethysmography. This development opens the door to ever-more sensitive piezoelectric sensors, crucial for applications including and beyond healthcare.

The 3D freeze printing (3DFP) of nanocellulose aerogels are demonstrated with large-scale aligned pore orientations as a sustainable alternative to current acoustical materials. In contrast with the unidirectional pore network orientations obtained from current 3DFP techniques, a bidirectional orientation is achieved by using an inhomogeneous printing substrate to alter the thermal gradient within the print volume. The microstructural morphology shows that bidirectional printing results in a 2D pore orientation, with comparatively thinner pore walls and larger pore widths. Acoustic measurements reveal that altering the pore network characteristics significantly affects the acoustical behavior of the printed CNC aerogels; the wider pores allow the bidirectional CNC aerogels to provide higher sound absorption performance at lower frequencies than the unidirectional samples. Notably, both 3D Freeze printed CNC aerogels provide substantially higher sound transmission loss performance as compared to current acoustical materials. The unidirectional pore structure results in CNC aerogels with higher stiffness and improved energy absorption performance, with both 3D freeze printed CNC aerogels outperforming other CNC aerogel materials in their stiffness-to-density ratios. The ability to simultaneously control their pore orientation and macrostructural geometry paves the way for printing complex shaped CNC aerogel structures for multifunctional noise control applications.