---
title: "Hydrogel photopolymerization method yields low-shrinkage ceramic and metal 3D structures"
url: https://www.voxelmatters.com/hydrogel-photopolymerization-method-yields-low-shrinkage-ceramic-and-metal-3d-structures/
date: 2025-10-29
modified: 2025-10-29
lang: en
author: "Davide Sher"
description: "A team of researchers at EPFL has demonstrated a new method for producing high-density ceramic and metal structures using vat photopolymerization (VP) with significantly reduced shrinkage [link to full study]...."
categories:
  - "Additive Manufacturing"
  - "AM Research"
  - "Ceramic Additive Manufacturing"
  - "Metal Additive Manufacturing"
  - "Research & Education"
tags:
  - "future"
image: https://www.voxelmatters.com/wp-content/uploads/2025/10/Hydrogel-photopolymerization-for-metal-and-ceramic-AM-640x426.jpg
word_count: 469
---

# Hydrogel photopolymerization method yields low-shrinkage ceramic and metal 3D structures

A team of researchers at EPFL has demonstrated a new method for producing high-density ceramic and metal structures using vat photopolymerization (VP) with significantly reduced shrinkage [[link to full study](https://advanced.onlinelibrary.wiley.com/doi/10.1002/adma.202504951)]. The process, based on repeated infusion-precipitation of metal ions into hydrogel scaffolds, enables the additive manufacturing of mechanically robust architectures with improved dimensional fidelity, density, and scalability—addressing long-standing limitations of traditional VP-based metal and ceramic fabrication.

## Decoupling shrinkage from material fidelity

Conventional VP techniques for non-polymeric materials rely on high-viscosity particle slurries or inorganic-organic hybrid photoresins, both of which suffer from poor print resolution, limited material selection, and high shrinkage during thermal conversion. While recent approaches using aqueous metal salt solutions have improved printability, they have historically yielded excessive linear shrinkage of 50–90%, which compromises structural integrity.

The new process, developed by Yiming Ji, Ying Hong, Dhruv R. Bhandari, and Daryl W. Yee, introduces a post-printing strategy that chemically transforms 3D-printed “blank” hydrogels into high-metal-content composites via repeated cycles of metal-ion infusion and in situ nanoparticle precipitation. Thermal treatment then converts the composites into dense ceramic or metallic structures. This infusion-precipitation approach allows metal-ion loadings of up to 79 wt%, which are significantly higher than those achievable with existing VP-compatible methods.

As a result, linear shrinkages were reduced to as low as 20% for ceramic oxides and 38–46% for metal structures, with theoretical densities exceeding 84%. Experimental measurements using microcomputed tomography confirmed these density gains. The reduction in shrinkage directly translated into improved mechanical performance, with iron structures fabricated via the new method achieving compressive strengths up to 5 MPa—more than 25 times higher than those made using earlier hydrogel-infusion additive manufacturing (HIAM) techniques.

## Enabling application-scale structures

In contrast to typical shrinkage-tolerant strategies that favor miniaturization, the low-shrinkage process expands the range of fabricable geometries and component sizes. The researchers successfully printed centimeter-scale iron gyroids, stents, gears, and sub-100 µm-walled silver lattices. The process was further extended to fabricate hard magnetic ceramics, such as strontium hexaferrite (SrFe₁₂O₁₉), demonstrating its ability to produce complex functional materials without altering base resin formulations.

The team highlighted the method's modularity and cost-effectiveness, which require only a standard digital light processing (DLP) printer, commercial metal salts, and a tube furnace—bypassing the expensive infrastructure and material constraints associated with powder bed fusion or selective laser sintering (SLS).

“This work opens up new capabilities for architected material design by overcoming long-standing trade-offs between shrinkage, fidelity, and material diversity in photopolymer-based additive manufacturing,” said Daryl W. Yee, Assistant Professor at EPFL and senior author of the study.

The study, published in Advanced Materials, suggests that the infusion-precipitation method could be adapted to other additive manufacturing platforms where optical clarity and feature resolution are paramount, including volumetric printing and two-photon lithography. The authors note that automating infusion cycles and hydrogel handling could further improve scalability for industrial applications.