Bispyrene Functionalization Drives Self-Assembly of Graphite Nanoplates into Highly Efficient Heat Spreader Foils

Abstract

Thermally conductive nanopapers fabricated from graphene and related materials are currently showing great potential in thermal management applications. However, thermal contacts between conductive plates represent the bottleneck for thermal conductivity of nanopapers prepared in the absence of a high temperature step for graphitization. In this work, the problem of ineffective thermal contacts is addressed by the use of bifunctional polyaromatic molecules designed to drive self-assembly of graphite nanoplates (GnP) and establish thermal bridges between them. To preserve the high conductivity associated to a defect-free sp 2 structure, non-covalent functionalization with bispyrene compounds, synthesized on purpose with variable tethering chain length, was exploited. Pyrene terminal groups granted for a strong π–π interaction with graphene surface, as demonstrated by UV–Vis, fluorescence, and Raman spectroscopies. Bispyrene molecular junctions between GnP were found to control GnP organization and orientation within the nanopaper, delivering significant enhancement in both in-plane and cross-plane thermal diffusivities. Finally, nanopapers were validated as heat spreader devices for electronic components, evidencing comparable or better thermal dissipation performance than conventional Cu foil, while delivering over 90% weight reduction.

Polycaprolactone Adsorption and Nucleation onto Graphite Nanoplates for Highly Flexible, Thermally Conductive, and Thermomechanically Stiff Nanopapers

“…The morphology of nanopapers in cross-section was investigated by SEM ( Figure 1 ), showing strong orientation as a consequence of filtration from suspension of nanoflakes, accordingly to our previous report. 56 Furthermore, the presence of an additional phase is observed in composite nanopapers, which is more clearly visible in nanopapers prepared with higher PCL/GNP ratios, suggesting a higher PCL content in the obtained materials. Qualitatively, PCL appears strongly adhered to GNP ( Figure 1 b) and likely intercalated between thin galleries observed in pristine GNP nanopaper ( Figure 1 a).…”

“…Envisaging application of these flexible PCL/GNP nanopapers as heat spreaders, thermal diffusivity was measured and reported in Table . Pristine GNP nanopapers have a thermal diffusivity in the range of 150 mm 2 /s, which may be competitive with traditional metal foils. , Diffusivity values for the GNP/PCL nanopapers are slightly reduced to 146 ± 2, 127 ± 1, and 138 ± 5 mm 2 /s for PCL1-GNP1-H, PCL5-GNP1-H, and PCL10-GNP1-H, according with the inclusion of a poorly conductive polymer.…”

“…GNP powder (50 mg) was added to the prepared PCL solutions. Homogeneous suspensions (with no obvious big GNP particles when transferred to the filter) were obtained by applying a previously validated 56 sonication treatment in pulsed mode (5 s on and 5 s off) for 30 min with power set at 30% of the full output power (500 W), accomplished with an ultrasonication probe (Sonics Vibracell VC-505, Sonics & Materials Inc.) with a 13 mm diameter Ti-alloy tip. The suspension was transferred into a filtration system equipped with a polyamide (PA) supported membrane (0.45 μm nominal pore size, diameter 47 mm, Whatman) and left for filtration overnight.…”

A universal concept for area‐selective assembly of metal oxide core‐shell nanoparticles, nanorods, and organic molecules via amide coupling reactions

“…As a complementary performance, the overhead layer as a functional NM can be additionally functionalized by fluorescent pyrene molecules in order to enhance the electric conductive properties of nanohybrid. [ 38–42 ]…”

“…As a complementary performance, the overhead layer as a functional NM can be additionally functionalized by fluorescent pyrene molecules in order to enhance the electric conductive properties of nanohybrid. [38][39][40][41][42] F I G U R E 1 Schematic representation of self-assembling PHA and AMPA SAM molecules on pristine NPs and NRs Herein, we display the new setup with simple and universal approach of organic-inorganic nanohybrid with 1aminopyrene molecules and favorable electrical-thermalmechanical properties, which may be relevant in thinfilm memory nanoelectronics. Additionally, we present a fabrication protocol of precise area-selective, controlled order and homogeneity of assembly of metal oxide coreshell NMs layer-by-layer thin-film formation in solution as ternary NPs-NRs-NPs.…”