# Bond-Reversibility Effects on Self-Crowding of Unimacromolecular Nano-Objects

## TL;DR

This study explores how reversible bonds affect the behavior of polymers in different concentrations, revealing that their size remains stable even when crowded.

## Contribution

The research introduces new insights into the behavior of reversibly bonding polymers under crowding conditions.

## Key findings

- Reversibly bonding polymers do not shrink under crowding conditions.
- The size and scaling exponent of these polymers remain unperturbed by crowding.
- Many-body effects are negligible in crowded systems of reversibly bonding polymers.

## Abstract

The scaling behavior of linear chains with reversible
bonds and,
in particular, its dependence on the concentration are fundamental
problems of polymer physics that are not fully understood. By means
of small-angle neutron scattering we investigate the conformations
of reversibly bonding polymers from high dilution (where they form
unimacromolecular nano-objects, usually known as single-chain nanoparticles)
to crowded solutions and bulk state far above the overlap concentration
(where they are expected to form a dynamic polymer network). Unlike
the cases of simple linear chains with no bonds and of chains with
strictly intramolecular irreversible bonds, no shrinkage is found,
and the size and scaling exponent of the reversibly bonding polymers
are essentially unperturbed by crowding. This is a relevant result
that confirms the negligibility of many-body effects beyond the overlap
concentration in crowded systems of reversibly bonding polymers and
the validity of ultrasoft effective interactions for predicting their
structural and phase behavior.