3 research outputs found
Three-Dimensional Printing of Cytocompatible, Thermally Conductive Hexagonal Boron Nitride Nanocomposites
Hexagonal
boron nitride (hBN) is a thermally conductive yet electrically
insulating two-dimensional layered nanomaterial that has attracted
significant attention as a dielectric for high-performance electronics
in addition to playing a central role in thermal management applications.
Here, we report a high-content hBN-polymer nanocomposite ink, which
can be 3D printed to form mechanically robust, self-supporting constructs.
In particular, hBN is dispersed in polyÂ(lactic-<i>co</i>-glycolic acid) and 3D printed at room temperature through an extrusion
process to form complex architectures. These constructs can be 3D
printed with a composition of up to 60% vol hBN (solids content) while
maintaining high mechanical flexibility and stretchability. The presence
of hBN within the matrix results in enhanced thermal conductivity
(up to 2.1 W K<sup>–1</sup> m<sup>–1</sup>) directly
after 3D printing with minimal postprocessing steps, suggesting utility
in thermal management applications. Furthermore, the constructs show
high levels of cytocompatibility, making them suitable for use in
the field of printed bioelectronics
Combustion-Assisted Photonic Annealing of Printable Graphene Inks via Exothermic Binders
High-throughput
and low-temperature processing of high-performance nanomaterial inks
is an important technical challenge for large-area, flexible printed
electronics. In this report, we demonstrate nitrocellulose as an exothermic
binder for photonic annealing of conductive graphene inks, leveraging
the rapid decomposition kinetics and built-in energy of nitrocellulose
to enable versatile process integration. This strategy results in
superlative electrical properties that are comparable to extended
thermal annealing at 350 °C, using a pulsed light process that
is compatible with thermally sensitive substrates. The resulting porous
microstructure and broad liquid-phase patterning compatibility are
exploited for printed graphene microsupercapacitors on paper-based
substrates
Enhanced Conductivity, Adhesion, and Environmental Stability of Printed Graphene Inks with Nitrocellulose
Recent
developments in liquid-phase processing of carbon nanomaterials
have established graphene as a promising candidate for printed electronics.
Of great importance in the ink formulation is the stabilizer, which
has to provide excellent dispersion stability and tunability in the
liquid state, and also decompose into chemical moieties that promote
high electrical conductivity and robust mechanical and environmental
stability. Here we demonstrate the promise of nitrocellulose as a
synergistic polymer stabilizer for graphene inks. Graphene processed
with nitrocellulose is formulated into inks with viscosities ranging
over 4 orders of magnitude for compatibility with a wide range of
deposition methods. Following thermal treatment, the graphene/nitrocellulose
films offer high electrical conductivity of ∼40 000
S/m, along with mechanical flexibility. Moreover, in contrast to state-of-the-art
graphene inks based on ethyl cellulose, the nitrocellulose residue
offers superior mechanical and environmental stability as assessed
by a suite of stress tests, including the Scotch tape test, a water
sonication test, and an 85/85 damp heat test. By exploring the fundamental
chemistry underlying these macroscopic benefits, we provide insight
into binder selection for functional nanomaterial inks while producing
a high-performance graphene ink with strong potential for printed
and flexible electronics