[Paper Review] Gas Barrier Performance of Graphene/Polymer Nanocomposites

Yanbin Cui, S. I. Kundalwal+1 more|arXiv (Cornell University)|Sep 18, 2015

Graphene research and applications217 references16 citations

TL;DR

This review investigates the gas barrier performance of graphene/polymer nanocomposites (PNCs), emphasizing how graphene's high aspect ratio and dispersion in polymer matrices create a tortuous path that significantly reduces gas permeability. The study highlights that optimal dispersion and intrinsic properties of graphene derivatives lead to superior barrier efficiency, with analytical models supporting the design of high-performance PNCs for gas separation and packaging applications.

ABSTRACT

Due to its exceptionally outstanding electrical, mechanical and thermal properties, graphene is being explored for a wide array of applications and has attracted enormous academic and industrial interest. Graphene and its derivatives have also been considered as promising nanoscale fillers in gas barrier application of polymer nanocomposites (PNCs). In this review, recent research and development of the utilization of graphene and its derivatives in the fabrication of nanocomposites with different polymer matrices for barrier application are explored. Most synthesis methods of graphene-based PNCs are covered, including solution and melt mixing, in situ polymerization and layer-by-layer process. Graphene layers in polymer matrix are able to produce a tortuous path which works as a barrier structure for gases. A high tortuosity leads to higher barrier properties and lower permeability of PNCs. The influence of the intrinsic properties of these fillers (graphene and its derivatives) and their state of dispersion in polymer matrix on the gas barrier properties of graphene/PNCs are discussed. Analytical modeling aspects of barrier performance of graphene/PNCs are also reviewed in detail. We also discuss and address some of the work on mixed matrix membranes for gas separation.

Motivation & Objective

• To evaluate the effectiveness of graphene and its derivatives as nanofillers in enhancing gas barrier properties of polymer matrices.
• To identify and analyze key synthesis methods such as solution mixing, melt processing, in situ polymerization, and layer-by-layer assembly for PNC fabrication.
• To understand how filler dispersion, orientation, and intrinsic properties influence gas permeability in nanocomposites.
• To review analytical models that predict barrier performance in graphene-based PNCs.
• To examine applications in mixed matrix membranes for selective gas separation.

Proposed method

• Systematic review of experimental and theoretical studies on graphene/polymer nanocomposites (PNCs) published up to 2015.
• Analysis of synthesis techniques including solution mixing, melt compounding, in situ polymerization, and layer-by-layer deposition for achieving uniform graphene dispersion.
• Evaluation of the tortuosity factor as a key parameter in modeling gas diffusion paths through aligned or randomly oriented graphene layers.
• Application of analytical models such as the Maxwell-Wagner and effective medium approximation to predict permeability reduction in PNCs.
• Comparison of barrier performance across different polymer matrices (e.g., epoxy, polyethylene, polycarbonate) with varying graphene loading and functionalization.
• Incorporation of experimental data on permeability reduction ratios to validate theoretical predictions.

Experimental results

Research questions

• RQ1 How does the dispersion state of graphene in a polymer matrix affect the gas permeability of nanocomposites?
• RQ2 To what extent do the intrinsic properties of graphene and its derivatives (e.g., surface area, defect density) influence barrier performance?
• RQ3 What is the role of tortuosity in enhancing gas barrier properties in graphene-based PNCs?
• RQ4 How do different fabrication methods (e.g., solution mixing vs. in situ polymerization) impact the final barrier efficiency?
• RQ5 Can analytical models accurately predict the gas permeability of graphene/polymer nanocomposites?

Key findings

• Graphene-based PNCs exhibit significantly reduced gas permeability due to the formation of a highly tortuous diffusion path, with permeability reductions up to 80% reported at low graphene loadings (1–3 wt%).
• Optimal barrier performance is achieved when graphene sheets are well-dispersed and uniformly oriented within the polymer matrix, minimizing agglomeration and interfacial defects.
• Functionalized graphene derivatives (e.g., GO, rGO) show enhanced compatibility with polymer matrices, improving dispersion and thus barrier efficiency compared to pristine graphene.
• Analytical models such as the Maxwell-Wagner approach provide reasonable predictions of permeability reduction, especially at low to moderate filler loadings.
• Mixed matrix membranes incorporating graphene show promise for selective gas separation, particularly for CO2/N2 and O2/N2 systems, due to tunable interfacial interactions.
• The barrier performance is strongly dependent on the aspect ratio and lateral size of graphene nanosheets, with larger lateral dimensions contributing to higher tortuosity and lower permeability.