High Internal Phase Emulsion Templating for Porous Polymer Development

High internal phase emulsion templating is a versatile route to produce porous polymers with highly interconnected architectures and tunable pore sizes. In this approach, a concentrated emulsion—typically water dispersed in oil or vice versa—serves as a sacrificial template: the continuous phase is polymerised around densely packed internal phase droplets, which are subsequently removed or transformed to generate voids. By adjusting formulation parameters such as phase volume ratio, surfactant concentration and monomer chemistry, researchers can control pore diameter, interconnectivity and overall porosity (often exceeding 80 %). The resulting polyHIPE materials combine lightweight structure with high surface area, making them attractive for applications ranging from tissue engineering scaffolds and filtration media to catalysis, energy storage and separation technologies. Integration with additive manufacturing techniques further enables hierarchical designs that span micro- to macroscopic scales, while functionalisation strategies expand chemical diversity and application scope.

Research from Nature Portfolio

A foundational study reported polyester-based polyHIPE scaffolds tailored for cartilage regeneration. By optimising droplet size and internal phase volume to achieve ~85 % porosity with primary pores of 50–170 µm, the scaffold supported human articular chondrocyte adhesion and infiltration to depths of 300 µm. Neocartilage formed in vitro exhibited a favourable collagen type II-to-I ratio and mechanical properties comparable to native tissue, while controlled biodegradation matched the timescale of matrix deposition. This work highlighted the capacity of emulsion-templated polymers to mimic complex tissue environments and underscored their translational potential in orthopaedic repair.

Research from all publishers

In energy materials, researchers have combined high internal phase emulsions with vat photopolymerisation and pyrolysis to fabricate hierarchically porous carbon lattices. Surfactant-stabilised emulsions of acrylate monomers were 3D-printed into lattices with dual-scale porosity (10 µm and 100 µm), then carbonised at up to 800 °C. Controlled shrinkage during pyrolysis yielded interconnected carboHIPE structures with high surface areas and tailored pore distributions, demonstrating promise for supercapacitors and catalytic supports. In the biomedical arena, highly elastomeric polyHIPEs based on poly(glycerol sebacate) methacrylate have been processed into complex vascular graft geometries—straight tubes, bends, branches and valves—via injection moulding. These scaffolds exhibited tunable mechanics and degradation kinetics, and perfusion culture confirmed robust support of vascular smooth muscle cell alignment and proliferation under flow.

High Internal Phase Emulsion Templating for Porous Polymer Development publication trend

The graph below shows the total number of articles in high internal phase emulsion templating for porous polymer development across all publications each year (not limited to Nature Index journals).

Technical terms

High internal phase emulsion (HIPE): A concentrated emulsion in which the volume fraction of the dispersed phase exceeds 74 %, creating a jammed droplet packing that templates porous structures upon polymerisation.

PolyHIPE: A porous polymer formed by curing the continuous phase of a HIPE, where the dispersed droplets leave behind an interconnected network of voids.

Emulsion templating: A technique that uses emulsions as sacrificial templates; removal or transformation of the dispersed phase yields controlled porosity.

Interconnected porosity: A pore network in which voids are linked by windows or throats, facilitating efficient transport of fluids, cells or gases.

Pyrolysis: Thermal decomposition of polymer templates under inert atmosphere, converting them into carbonaceous materials while preserving porous morphology.

References

1. Basic Principles of Emulsion Templating and Its Use as an Emerging Manufacturing Method of Tissue Engineering Scaffolds. Frontiers in Bioengineering and Biotechnology (2020).
2. Polyester type polyHIPE scaffolds with an interconnected porous structure for cartilage regeneration. Scientific Reports (2016).
3. Fabrication of hierarchically porous carbon lattices derived from 3D-Printed polymerized high internal phase emulsions. Carbon (2025).
4. Versatile, elastomeric and degradable polyHIPEs of poly(glycerol sebacate)-methacrylate and their application in vascular graft tissue-engineering. Materials Today Advances (2023).