Diffusion across a gel-gel interface-molecular-scale mobility of self-assembled 'solid-like' gel nanofibres in multi-component supramolecular organogels

TY - JOUR

T1 - Diffusion across a gel-gel interface-molecular-scale mobility of self-assembled 'solid-like' gel nanofibres in multi-component supramolecular organogels

AU - Ruíz-Olles, Jorge

AU - Smith, David K.

N1 - © The Royal Society of Chemistry, 2018.

PY - 2018/7/7

Y1 - 2018/7/7

N2 - This paper explores macroscopic-scale diffusion of the molecular-scale building blocks of two-component self-assembled organogel nanofibres using a diffusion cell in which two different gels are in contact with one another. Both components of the 'solid-like' nanofibres (lysine peptide dendron acids and amines) can diffuse through these gels and across a gel-gel interface, although diffusion is significantly slower than that of a non-interactive additive in the 'liquid-like' phase of the gel. Amine diffusion was probed by bringing similar gels with different amines into contact. Dendron acid diffusion was tested by bringing similar gels with enantiomeric dendrons into contact. Surprisingly, dendron and amine diffusion rates were similar, even though the peptide dendron is more intimately hydrogen bonded in the self-assembled nanofibres. It is proposed that thermal disassembly of the acid-amine complex delivers both components into the liquid-like phase, allowing them to diffuse via a decomplexation/recomplexation mechanism. This is a rare observation in which molecules assembled into solid-like gel nanofibres are mobile-in dynamic equilibrium with the liquid-like phase. Gel nanofibre diffusion and reorganisation are vital in understanding dynamic materials processes such as metastability, self-healing and adaptability.

AB - This paper explores macroscopic-scale diffusion of the molecular-scale building blocks of two-component self-assembled organogel nanofibres using a diffusion cell in which two different gels are in contact with one another. Both components of the 'solid-like' nanofibres (lysine peptide dendron acids and amines) can diffuse through these gels and across a gel-gel interface, although diffusion is significantly slower than that of a non-interactive additive in the 'liquid-like' phase of the gel. Amine diffusion was probed by bringing similar gels with different amines into contact. Dendron acid diffusion was tested by bringing similar gels with enantiomeric dendrons into contact. Surprisingly, dendron and amine diffusion rates were similar, even though the peptide dendron is more intimately hydrogen bonded in the self-assembled nanofibres. It is proposed that thermal disassembly of the acid-amine complex delivers both components into the liquid-like phase, allowing them to diffuse via a decomplexation/recomplexation mechanism. This is a rare observation in which molecules assembled into solid-like gel nanofibres are mobile-in dynamic equilibrium with the liquid-like phase. Gel nanofibre diffusion and reorganisation are vital in understanding dynamic materials processes such as metastability, self-healing and adaptability.

UR - http://www.scopus.com/inward/record.url?scp=85049246281&partnerID=8YFLogxK

U2 - 10.1039/c8sc01071d

DO - 10.1039/c8sc01071d

M3 - Article

AN - SCOPUS:85049246281

SN - 2041-6520

VL - 9

SP - 5541

EP - 5550

JO - Chemical Science

JF - Chemical Science

IS - 25

ER -