Solvent Interfacial Trapping Method (SITM)

The Solvent Interfacial Trapping Method (SITM) represents a thermodynamically-driven approach for the exfoliation of layered materials without chemical modification. This method exploits the energetic penalty associated with displacing two-dimensional materials from liquid-liquid interfaces to achieve spontaneous exfoliation and stabilization of pristine graphene and related 2D materials.

Mechanism and Principles

When graphite is introduced to the interface between immiscible liquids (such as water and heptane or other organic solvents), spontaneous exfoliation occurs as individual graphene sheets minimize the system’s free energy by spreading at the high-energy interface. The significant energetic cost of moving graphene sheets into either bulk liquid phase effectively traps them at the interface, preventing restacking through van der Waals interactions.

This interfacial stabilization enables the formation of water-in-oil emulsions where graphene functions as a 2D surfactant. Simple agitation promotes the creation of additional interfaces, driving further exfoliation while maintaining the structural integrity of the graphene sheets. The method utilizes natural flake graphite with various organic solvents or monomers, providing access to diverse composite materials through subsequent polymerization or film formation processes.

Key Publications

Foundational Work

Conductive Thin Films of Pristine Graphene by Solvent Interface Trapping
Woltornist, S.J.; Oyer, A.J.; Carrillo, J.-M.Y.; Dobrynin, A.V.; Adamson, D.H.
ACS Nano 2013, 7, 7062-7066

This seminal work established the SITM methodology, demonstrating the assembly of macroscopic pristine graphene films with up to 95% optical transparency and conductivities of approximately 400 S/cm. The study utilized modest sonication of natural flake graphite in water/heptane mixtures to form continuous films at the liquid-liquid interface.

Recent Advances (2024-2025)

Transparent Conductive PEDOT–Graphene Films from Large-Flake Graphite
McDermott, S.T.; Ferland, B.; Liu, J.; Abeykoon, P.; Joyce, M.J.; Shuster, S.; Suib, S.L.; Adamson, D.H.
Synthetic Metals 2025, 312, 117866

Electrically Conducting Porous Hydrogels by a Self-Assembled Percolating Pristine Graphene Network
Sejoubsari, R.M.; Xu, T.O.; Ward, S.P.; Bandara, N.M.; Zhang, Z.; Adamson, D.H.
Soft Matter 2025, 21, 1225-1232

Hexagonal Boron Nitride as a Two-Dimensional Surfactant: Low-Density Flame-Resistant Composites Based on Boron Nitride Exfoliated by an Interface Trapping Technique
Chapman, C.M.; Srivastava, D.S.; Ward, S.P.; Cui, Z.; Adamson, D.H.
ACS Applied Materials & Interfaces 2024, 16, 69901-69907

Extension of the interface trapping methodology to hexagonal boron nitride, demonstrating the broader applicability of SITM to other layered materials beyond graphene.

Composite Materials and Applications

PolyHIPE Foams from Pristine Graphene: Strong, Porous, and Electrically Conductive Materials Templated by a 2D Surfactant
Brown, E.E.B.; Woltornist, S.J.; Adamson, D.H.
Journal of Colloid and Interface Science 2020, 580, 700-708

Utilization of monomers as the oil phase in SITM enables formation of polymerized high-internal phase emulsions (polyHIPEs). These materials exhibit low density, electrical conductivity, and mechanical robustness with compressive strengths of 7.0 MPa at densities of 0.22 g/cm³.

Interface-Exfoliated Graphene-Based Conductive Screen-Printing Inks: Low-Loading, Low-Cost, and Additive-Free
Chen, F.; Varghese, D.; McDermott, S.T.; George, I.; Geng, L.; Adamson, D.H.
Scientific Reports 2020, 10, 18047

Self-Assembled Graphene Composites for Flow-Through Filtration
Varghese, D.; Bento, J.L.; Ward, S.P.; Adamson, D.H.
ACS Applied Materials & Interfaces 2020, 12, 29692-29699

Mechanistic Studies

Kinetic Study of Surfactant-Free Graphene Exfoliation at a Solvent Interface
Hui, T.; Adamson, D.H.
Carbon 2020, 168, 354-361

Effect of Aqueous Anions on Graphene Exfoliation
Ward, S.P.; Abeykoon, P.G.; McDermott, S.T.; Adamson, D.H.
Langmuir 2020, 36, 10421-10428

Chromatographic Approach to Isolate Exfoliated Graphene
Abeykoon, P.G.; Ward, S.P.; Chen, F.; Adamson, D.H.
Langmuir 2021, 37, 9378-9384

Pristine Graphene Microspheres by the Spreading and Trapping of Graphene at an Interface
Liyanage, C.D.; Varghese, D.; Brown, E.E.B.; Adamson, D.H.
Langmuir 2019, 35, 14310-14315

Theoretical and Computational Studies

Electrical Conductivity of Graphene–Polymer Composite Foams: A Computational Study
Wang, Z.; Tian, Y.; Liang, H.; Adamson, D.H.; Dobrynin, A.V.
Macromolecules 2019, 52, 7379-7385

From Graphene-like Sheet Stabilized Emulsions to Composite Polymeric Foams: Molecular Dynamics Simulations
Wang, Z.; Liang, H.; Adamson, D.H.; Dobrynin, A.V.
Macromolecules 2018, 51, 7360-7367

Material Properties and Characterization

Controlled 3D Assembly of Graphene Sheets to Build Conductive, Chemically Selective and Shape-Responsive Materials
Woltornist, S.J.; Varghese, D.; Massucci, D.; Cao, Z.; Dobrynin, A.V.; Adamson, D.H.
Advanced Materials 2017, 29, 1604947

Thermal and Electrical Properties of Nanocomposites Based on Self-Assembled Pristine Graphene
Bento, J.L.; Brown, E.B.; Woltornist, S.J.; Adamson, D.H.
Advanced Functional Materials 2017, 27, 1604277

Properties of Pristine Graphene Composites Arising from the Mechanism of Graphene-Stabilized Emulsion Formation
Woltornist, S.J.; Adamson, D.H.
Industrial & Engineering Chemistry Research 2016, 55, 6777-6782

Polymer/Pristine Graphene Based Composites: From Emulsions to Strong, Electrically Conducting Foams
Woltornist, S.J.; Carrillo, J.-M.Y.; Xu, T.; Dobrynin, A.V.; Adamson, D.H.
Macromolecules 2015, 48, 687-693

Preparation of Conductive Graphene/Graphite Infused Fabrics Using an Interfacial Trapping Method
Woltornist, S.J.; Alamer, F.A.; McDannald, A.; Jain, M.; Sotzing, G.A.; Adamson, D.H.
Carbon 2015, 81, 38-42