# Degradable polyphosphoester-based aqueous two-phase systems and water-in-water emulsions

## TL;DR

This paper introduces water-based systems that can be broken down on demand, offering new possibilities for molecular separation and material design.

## Contribution

The novelty lies in using degradable polymers to create controllable aqueous two-phase systems and emulsions.

## Key findings

- Aqueous two-phase systems were formed using dextran and poly(ethylene ethyl phosphonate).
- Silica nanoparticles stabilized water-in-water emulsions in the system.
- Polymer degradation was shown to break the two-phase systems or emulsions.

## Abstract

Completely water-based multicompartment systems have gained significant interest in polymer chemistry recently, mainly due to their interesting properties for molecular separation, material design and catalytic environments. Herein, we present new aqueous two-phase systems and water-in-water emulsions based on a polysaccharide and a polyphosphoester, namely dextran (Dex) and poly(ethylene ethyl phosphonate) (PPE), respectively. The aqueous two-phase formation is investigated via a phase diagram, and water-in-water emulsions are formed making use of silica nanoparticles as stabilizers. The system is designed to investigate the effect of polymer orthogonal degradation and the role of either Dex or PPE in breaking the two-phase systems or the emulsions. This development is a considerable step forward enhancing control over aqueous multi-phase systems, by making use not only of polymer components but also of their degradation to design desired properties. These properties might be a relevant avenue for developments in the research area of all-aqueous systems for encapsulation, delivery and release as well as membraneless-organelle mimics.

New aqueous two-phase systems and water-in-water emulsions are described that feature triggered degradation.