# Initiator-Free Recyclable Anthracene-Based Photocurable Resin Enabling Sustainable 3D Printing via Single- and Two-Photon Stereolithography

## TL;DR

A new recyclable resin for 3D printing allows structures to be reused multiple times without losing quality, using light to switch between solid and liquid states.

## Contribution

The study introduces an initiator-free, recyclable anthracene-based resin for sustainable 3D printing via single- and two-photon techniques.

## Key findings

- The resin enables over ten reprocessing cycles with minimal degradation.
- It works with both single- and two-photon lithography techniques.
- The resin uses reversible photodimerization without photoinitiators or additives.

## Abstract

Single- and two-photon stereolithography are high-resolution
three-dimensional
(3D) printing techniques that are widely used to fabricate complex
microstructures. However, the resulting structures have high cross-linking
and density, which limits their recyclability. Existing approaches
to addressing this issue typically rely on chain-growth polymerization,
which requires photoinitiators and additional reagents for recycling.
In this study, we present an anthracene-based photocurable resin that
undergoes reversible photodimerization, enabling phase transitions
between the solid and liquid states without photoinitiators or additives.
Using this resin, we fabricated and recycled 3D microstructures via
two-photon lithography, demonstrating over ten successful reprocessing
cycles with minimal degradation. In addition, the resin is also compatible
with single-photon microstereolithography, highlighting its versatility.
These findings suggest a promising route for sustainable high-resolution
additive manufacturing.