Microtube self-assembly leads to conformational freezing point depression

TL;DR

This study investigates how the conformation of concentric microtubes influences their melting behavior, revealing a new phenomenon called conformational freezing point depression through in situ X-ray scattering.

Contribution

It introduces the concept of conformational freezing point depression and provides a model explaining the energetics of microtube self-assembly without free parameters.

Findings

Concentric microtubes grow from outside in and melt from inside out.

Conformation affects saturation concentration in the system.

The proposed model explains the energetics based on freezing point depression.

Abstract

Concentric microtubes of $\beta$-cyclodextrin and SDS grow from the outside in and melt from the inside out, we observe using in situ small angle X-ray scattering. We find that the conformation of the crystalline bilayer affects the saturation concentration, providing an example of a phenomenon we call conformational freezing point depression. We propose a model based on freezing point depression, well known from undergraduate physics, and use it to explain the energetics of this hierarchical system, and giving access to material properties without free parameters.