We discuss the current state of characterising multicomponent low molecular weight gels across all length scales, and the effectiveness of the different techniques that have been used.

A number of Fmoc amino acids can be effective low molecular weight hydrogelators. The type of gel formed depends on the amino acid used and, in the case of FmocF, the final pH of the system. The single crystal structure of two of the gelators (FmocF and FmocY) have been determined and the data compared to the fibre X-ray diffraction data. FmocF, which forms metastable gels, crystallises easily and the data for the fibre phase and crystal phase are relatively similar. For FmocF, the fibre axis in b is consistent with the hydrogen bonding repeat distances and the diffraction pattern calculated from the single crystal structure is a good match with the experimental fibre X-ray diffraction data. On the other hand, there are significant differences between the crystalline phase determined and the fibre phase for FmocY. The packing of FmocY within the crystal structure is created by interactions between the planar Fmoc groups, whilst it is clear that hydrogen bonding drives the self-assembly into fibrillar structures within the gels. This shows that understanding the packing in gel phase by analogy to isolated crystal structures has the potential to lead to erroneous conclusions.

Low molecular weight gels are formed by the self-assembly of small molecules into fibrous networks that can immobilise a significant amount of solvent. Here, we focus on our work with a specific class of gelator, the functionalised dipeptide. We discuss the current state of the art in the area, focusing on how these materials can be controlled. We also highlight interesting and unusual observations and unanswered questions in the field.

Hydrogels prepared from low molecular weight gelators (LMWGs) are formed as a result of hierarchical intermolecular interactions between gelators to form fibres, and then further interactions between the self-assembled fibres via physical entanglements, as well as potential branching points. These interactions can allow hydrogels to recover quickly after a high shear rate has been applied. There are currently limited design rules describing which types of morphology or rheological properties are required for a LMWG hydrogel to be used as an effective, printable gel. By preparing hydrogels with different types of fibrous network structures, we have been able to understand in more detail the morphological type which gives rise to a 3D-printable hydrogel using a range of techniques, including rheology, small angle scattering and microscopy.

Multicomponent supramolecular gels have great potential for optoelectronics. Ideally, we could con-trol the self-assembly of multiple components across many length scales, from the primary as-sembled structures to how these are arranged in space. This would allow energy transfer between p-type and n-type fibers to be controlled. Usually, a single network is formed and analyzed. It is not clear how most networks could be modified, and certainly not how these might be differentiated. Here, we address both of these issues. We show how the different components in a multicomponent gel can be differentiated by small angle neutron scattering (SANS) using contrast matching experi-ments. The rate of self-assembly can be used to vary the networks that are formed, leading directly to changes in the efficiency of electron transfer. The assembly kinetics can therefore be used to prepare different networks from the same primary building blocks and primary self-assembled struc-tures. We expect that these advances will allow multicomponent systems to become effective elec-tronic materials.

A simple heat/cool cycle can be used to significantly affect the properties of a solution of a low‐molecular‐weight gelator at high pH. The viscosity and extensional viscosity are increased markedly, leading to materials with very different properties than when the native solution is used.