# Constructing Multifunctional Composite Single Crystals via Polymer Gel Incorporation

## TL;DR

This paper explores how incorporating polymer gels into single crystals creates multifunctional composite materials with unique properties.

## Contribution

The paper reviews the mechanisms and applications of gel-incorporated single crystals inspired by biominerals.

## Key findings

- Gel incorporation allows for composite single crystals with bi-continuous interpenetrating structures.
- Dyes and nanoparticles can be embedded in single crystals using gel guidance.
- Applications include crystal morphology control and optoelectronics.

## Abstract

The non-uniformity of a single crystal can sometimes be found in biominerals, where surrounding biomacromolecules are incorporated into the growing crystals. This unique composite structure, combining heterogeneity and long-range ordering, enables the functionalization of single crystals. Polymer gel media are often used to prepare composite single crystals, in which the growing crystals incorporate gel networks and form a bi-continuous interpenetrating structure without any disruption to single crystallinity. Moreover, dyes and many kinds of nanoparticles can be occluded into single crystals under the guidance of gel incorporation. On this basis, the bio-inspired method has been applied in crystal morphology control, crystal dyeing, mechanical reinforcement, and organic bulk heterojunction-based optoelectronics. In this paper, the composite structure, the incorporation mechanisms, and the multiple functions of gel-incorporated single crystals are reviewed.