Researchers at the Massachusetts Institute of Technology (MIT) have reported the development of a lightweight, two-dimensional polyaramid polymer that can serve as a protective coating for solar cells, electronics, and infrastructure.

The film, known as 2DPA-1, can be applied in thicknesses as thin as a few nanometers and can block nitrogen, helium, oxygen, methane, argon, and sulfur hexafluoride at levels significantly lower than those of any known polymer.

This degree of impermeability, demonstrated in a study published in Nature, positions the material as a potential barrier to slow degradation and corrosion in technologies such as perovskite solar cells, packaged pharmaceuticals, and structural materials exposed to environmental stressors.

Background and Structural Development

The development of 2DPA-1 builds on earlier work from 2022, when the material was first introduced as a two-dimensional polymer that self-assembles into nanometer-scale molecular sheets.

The polymer is synthesized via polycondensation using melamine and trimesoyl chloride. Under controlled solvent conditions such as trifluoroacetic acid or dimethyl sulfoxide, these reactions produce nanoplatelets roughly 10 nanometers in diameter.

The platelets stack on one another via strong hydrogen bonds, forming ordered layers with an interlayer distance of approximately 3.3 ± 0.2 angstroms. This stacking eliminates the free volume typically present in conventional polymers, which generally consist of entangled chains with small gaps that allow gas molecules to diffuse.

The films examined by the researchers ranged in thickness from 4 to 65 nanometers. Scanning transmission electron microscopy confirmed a regular lattice-like arrangement within the polymer, although the material itself is not a perfect crystal. This non-crystalline yet tightly packed structure allows the polymer to behave in ways previously observed only in crystalline two-dimensional materials such as graphene.

One of the most significant demonstrations in the study involved coating perovskite crystals with a 60-nanometer layer of 2DPA-1. Perovskites are considered a promising low-cost alternative to silicon for photovoltaics, but they degrade quickly when exposed to oxygen.

The coated perovskite samples showed a 14-fold reduction in lattice degradation rate compared to uncoated samples. The measured oxygen permeability for the coated system was approximately 3.3 × 10^–8 Barrer.

According to the researchers, a thicker coating could further extend the lifespan of perovskite-based devices.

Because 2DPA-1 is solution-processable, it can be applied in ways that traditional 2D materials like graphene cannot. Graphene’s defect-free crystalline structure gives it ideal barrier performance, but scaling up production and improving adhesion remain challenges.

Graphene layers tend to slide over one another due to low interlayer friction, hindering effective large-area coatings. The hydrogen-bonded structure of 2DPA-1 eliminates this issue and allows the polymer film to be formed uniformly across larger surfaces.

The authors note that the primary challenges ahead lie in producing large, defect-free films suitable for industrial deployment and verifying long-term performance under real environmental conditions.

However, the results demonstrate that solution-phase polymerization can produce materials with barrier properties previously thought achievable only in crystalline 2D materials, opening new avenues for protecting solar technologies and extending the operational life of devices and infrastructure.

In June this year, Researchers at the Massachusetts Institute of Technology demonstrated a new interface architecture that pushes the traditional silicon solar cell’s efficiency beyond the long-standing single-junction theoretical limit of 29.4%.