Graphite Fluoride for Flexible Thermal Films — Korea Nat'l UTE, 2020

Vu, M. et al. (2020). Highly flexible graphene derivative hybrid film: an outstanding nonflammable thermally conductive yet electrically insulating material for efficient thermal management. *ACS Applied Materials & Interfaces*. https://doi.org/10.1021/acsami.0c02427

ACS Applied Materials & Interfaces · 2020

Korea National University researchers exfoliated ACS Material graphite fluoride into GFS@rGO films reaching 212 W·m⁻¹·K⁻¹ thermal conductivity with electrical insulation.

About this research

Researchers at Korea National University of Transportation used graphite fluoride purchased from ACS Material to develop a highly flexible graphene-derivative hybrid film that delivers an in-plane thermal conductivity of 212 W·m⁻¹·K⁻¹ while remaining electrically insulating, addressing a long-standing trade-off in flexible electronics thermal management.

Portable electronics, LEDs, and high-power-density devices generate concentrated heat that degrades performance and reliability. Conventional metal heat spreaders conduct heat but short electrical pathways, while polymer films are insulating but thermally poor. Materials that simultaneously dissipate heat in-plane, block current, withstand bending, and resist flame are therefore in strong demand for next-generation foldable electronics.

The ACS Material graphite fluoride (CAS GTFF012, 200–500 μm lateral size) served as the starting material for the thermally conductive yet electrically insulating filler. The authors dispersed it in NMP and processed it by planetary ball milling at 300 rpm for 3, 6, and 12 h to exfoliate few-layer graphene fluoride sheets (GFS). TEM and AFM confirmed sheets roughly 2.2 nm thick (3–4 layers) with lateral sizes tunable from ~300 nm to ~1250 nm by milling time. The GFS was then co-filtered with graphene oxide and reduced with hydrogen iodide at 80 °C to give a 30-μm GFS@rGO hybrid film with highly ordered filler alignment.

The optimized films exhibited an in-plane thermal conductivity of 212 W·m⁻¹·K⁻¹ and a volume resistivity of 1.1 × 10¹¹ Ω·cm. Mechanical performance scaled with rGO loading, reaching a tensile strength of 69.3 MPa and a Young's modulus of 10.2 GPa at 20 wt % rGO, and the films tolerated repeated bending. Microscale combustion calorimetry showed a peak heat release rate of only 21 W·g⁻¹ at 323 °C for GFS@rGO10, compared with 198 W·g⁻¹ at 159 °C for a pure GO reference, and direct flame tests confirmed that the films prevented fire spreading. The high intrinsic phonon conductivity and clean basal plane of the ACS Material graphite fluoride were essential to achieving these combined thermal, dielectric, and flame-retardant properties.

How ACS Material products were used

• Graphite Fluoride (Carbon Monofluoride) (Graphene Series)  — “Graphite fluoride (CAS: GTFF012) with an average lateral size of 200−500 μm was purchased from ACS Material (USA).”

Product Performance in this Study

The ACS Material graphite fluoride was successfully exfoliated by ball milling into few-layer graphene fluoride sheets (~2 nm thick, 3–4 layers), serving as the principal thermally conductive yet electrically insulating filler that enabled the hybrid film to reach 212 W·m⁻¹·K⁻¹ in-plane thermal conductivity.

Related product categories

• Graphene Series