Dipeptides functionalized at the N-terminus with large aromatic groups are known to selfassemble in water. In many cases, micellar structures are formed at high pH. When the molecule is very hydrophobic, it is typical for worm-like micelles or nanotubes to be formed; less hydrophobic molecules typically self-assemble into ill-defined spherical structures. A range of different aromatic groups have been added to the N-terminus of dipeptides including Fmoc (fluorenylmethoxycarbonyl), naphthalene, phenanthrene, anthraquinone, and benzophenone. In many cases, these aromatic groups are essentially non-functional and act simply to provide hydrophobicity and -interactions to direct self-assembly. However, this does not have to be the case and indeed a benzophenone-functionalized dipeptide has been shown to be photoactive. Inspired by this, we synthesized three benzophenone-diphenylalanine conjugates: 3BPAcFF, 3BPFF and 4BPAcFF (Figure ). We varied the position at which the diphenylalanine is attached to the benzophenone as well as the linker between the benzophenone and dipeptide (see Supplementary Information for synthetic pathway and characterisation). In all cases, the Cterminus is free, meaning that we can use pH to control the self-assembly. To induce selfassembly, an aqueous dispersion at high pH (10.0±0.1, Figure ) was prepared from each conjugate at a concentration of 5, 10, or 20 mg mL -1 . At this pH, the carboxylic acid is deprotonated, leading to the formation of micellar aggregates (Figure insert). As their purpose was to be used as photoinitiations, we first recorded their absorption at both optically dilute (<0.01 mg mL -1 ) and micellar concentrations (10 mg mL -1 ), which were used to form the noodles (discussed later, Figure ). Each dipeptide showed a slight bathochromic shift in peak absorption in the concentrated solution compared to the molecularly dissolved solution, as expected when in the self-assembled state. Nevertheless, the benzophenone component remained evident, allowing us to use UV light to initiate polymerization at micellar concentrations. The micellar structures formed at a concentration of 10 mg mL -1 were probed using viscosity (Figure ) and small angle X-ray scattering (SAXS, Figure ). The viscosity of 3BPAcFF was very low, indicating a small presence of persistent structures in this material. The SAXS data best fits to a combined power law and cylinder model, with the cylinder component needed to account for the slight bump in the data at 0.03 Å -1 . This further implies a small concentration of wormlike structures present in solution. In comparison, more viscous solutions were formed by 3BPFF and a shear-thinning behaviour was observed, suggestive of the presence of more wormlike micelles. Indeed, the SAXS data are best fitted using a hollow cylinder model, with a radius of 36.8 nm and a thickness of 4.2 nm. 4BPAcFF formed significantly more viscous solutions, accompanied by shear-thinning behaviour. In line with the viscosity data, the SAXS data for 4BPAcFF are best fitted to a combined power law and cylinder model with a significant cylinder component arising from the micellar structures. On top of this, there is a peak at a Q value of 0.02 Å -1 . Like related systems, this peak represents the correlation length of the system, ξ, as these systems are behaving as polyelectrolytes. The peak position shows a concentration dependence (Figure ) and follows a scaling of ξ∼ c 1/2 as expected for wormlike micelles behaving as a polyelectrolyte chain (Figure ). We confirmed that each of the gelators could produce self-supporting bulk gels when triggered with calcium chloride (Figure ). However, our intention here was to prepare localized photoinitiators. To prepare these, we used a technique developed by Stupp's group, forming socalled supramolecular noodles. To form noodles, a viscous solution is required which is extruded into a crosslinking bath, herein an aqueous calcium chloride solution (0.5 M). We have previously described how this method can be manipulated to form long (multi-meter) noodles with controlled diameters. Using this approach, unsurprisingly considering the viscosity data described in Figure , only 4BPAcFF was found to form well-defined noodles when extruded into a bath containing the calcium salt crosslinker at a concentration at 10 mg mL -1 (Figure ). 3BPAcFF was found to give noodles that were extremely fragile such that they were unable to be lifted from the crosslinking bath. 3BPFF did not produce noodles, but produced randomly sized precipitates that did not interlock and were also unable to be removed (Figure ). The noodles prepared from 4BPAcFF were typically 500 µm in diameter (as determined by the extrusion needle, Figure ). Considering the formation process, to assess if there was a general alignment along the noodle backbone, the noodles were first viewed under a microscope with polarized light (Figure and). At 10 mg mL -1 , the noodles showed some birefringent behaviour, indicating a degree of alignment that is mimicked by the increased viscosity of 4BPAcFF. However, increasing the concentration of the pre-gelation solution to up 50 mg mL -1 did not result in any significant changes in the microscope imaging (Figure ). The mechanical properties of the 4BPAcFF noodles were then measured. To do this, we evaluated the Young's modulus (E) of the noodles by nanoindentation. This allows us to quantify the local mechanical properties at micron length scales. The Young's modulus is improved slightly as the concentration of the 4BPAcFF increased, although E is similar for the noodles prepared from 5, 10 and, 20 mg mL -1 micellar solutions (Figure ). We attempted to strengthen the noodles by subjecting the high pH solutions to heat-cool cycles at 70 °C pre-gelation; this has been shown to be effective for other bulk gel systems. However, in this case, this provided minimal benefit to the noodles in terms of their useability and mechanical strength. We therefore focused on 4BPAcFF at 10 mg mL -1 , which was the lowest concentration that can be easily manipulated by hand. Next, we investigated the use of 4BPAcFF as a photoinitiator. We selected a commercial 365 nm LED as our irradiation source, and although the absorption of the gelator and micellar solutions was relatively low at this wavelength, it was still sufficient to induce polymerization. A mixture of 4BPAcFF, a cross-linkable acrylate monomer [pentaerythritol tetraacrylate (PETA); in a 1:4 ratio, respectively], and DMSO-d6 solvent was irradiated in an NMR tube. Visually, it was clear that the polymerization proceeded after 5 minutes of irradiation, with a change in appearance from transparent to translucent (Figure ). Both the gelator and PETA signals broadened significantly (indicating successful polymerization), and the ratio of terminal alkene groups was reduced by approximately 20-fold after 30 minutes of irradiation. Additionally, we did not see any dimerization of the benzophenone component or significant degradation after irradiation in DMSO-d6, or after irradiating a piece of noodle for 1 hour (and freeze drying to allow for NMR, Figure ). With this confirmation that the benzophenone component of 4BPAcFF can still act as an efficient photoinitiator, we then sought to combine the two techniques. Localised polymerization was achieved using two distinct methods (see Figure for schematic). Firstly, the noodles were removed from the trigger medium and manually cut and arranged into the desired shape (here, a rod). The noodle template was then encased in the PETA monomer. We found that the high viscosity of PETA allowed the monomer to be coated over the noodle (instead of needing to completely immerse the noodle), and its low polarity and hydrophobicity did not dissolve the noodle template. To ensure a self-supporting polymer was formed, we irradiated the template/monomer composite for either 2 or 4 hours. The excess monomer, noodle template, and loose polymer aggregates were washed away with solvent (see Supporting Information) leaving the templated polymer (Figure ). Again, we viewed the newly formed structures under the microscope and when using polarized light. There was a distinct change in appearance from translucent to opaque, and on average, the noodles shrunk to approximately 300 µm after solvent washing. There was no general alignment visible in the cross-polarized light, however, the polymer structure was clearly localised to only where the gel noodle was positioned. Most interestingly, the Young's Modulus increased significantly from ≈16 kPa to ≈240 kPa after 2 hours, which continued to increase to ≈1820 kPa after 4 hours. This increase in stiffness can be ascribed to the crosslinked coating. For the second method, it was found that noodles could still be formed when the trigger solution was mixed with a water-soluble acrylate monomer, 2-hydroxyethyl acrylate (HEA). In a 1:4 ratio (monomer to calcium chloride, by volume) the noodles were still strong enough to be manually lifted from the solution, although they had to be polymerized quickly as the noodle would dissolve into randomly sized pieces and could no longer be lifted after approximately 1 hour. Additionally, the polymerization speed needed to be increased to account for their solubility in the mixture solution. Polymerization was achieved by irradiating the noodle in the trigger solution with two 365 nm LEDs positioned above and below the sample, at a closer distance to increase the flux to approximately 120 mW cm -2 . The newly templated polymers were softer and more flexible, compared to the PETA polymers which were brittle and more rigid. The noodles also typically swelled during the polymerization process, producing less defined structures that did not fully mimic the original noodle template (Figure ). We again viewed the structures under the microscope using cross-polarized light, which only showed some birefringent behaviour; however, there was still a visible change from translucent to opaque. After solvent washing, the noodles shrunk to around 300 µm, but unlike the PETA structures, these could be re-swollen to over 500 µm when sat in water (Figure ). The mechanical strength of the noodles was investigated by measuring the Young's modulus by nanoindentation. This again increased from the original noodle to ≈24 kPa (from ≈16 kPa) after 1 hour of irradiation and continued to increase slightly to ≈29 kPa after 2 hours. These results were consistent with using the HEA monoacrylate as the monomer, compared to the cross-linkable PETA, which produced stronger structures. Together, this demonstrates the ability to strengthen the functionalised noodles through selective polymerization to achieve targeted mechanical and physical properties. Finally, we showcased how the noodles can sculpt intricate shapes that localise the subsequent photopolymerization. To accommodate heating effects from prolonged irradiation, the polymerization conditions with the PETA monomer were slightly adjusted (see Supporting Information). The first structure was a bow-tie shape featuring an intersection, where two pieces of noodle overlapped. After solvent washing, the newly formed polymer was strong enough to be manually handled, and when viewed under the microscope (Figure ), it revealed the fusing of the intersection into a single piece. A cross-section of the polymer at the edge of the structure (Figure ) appeared hollow, with only an outer shell of polymer remaining in place of the noodle template. Finally, we demonstrated how a desired shape could be maintained by manually arranging the noodles and polymerizing. The letters 'UofG' were manually drawn and retained immediately after irradiation (Figure ), and after solvent washing (which also induces shrinkage, as seen previously), could be handled and rearranged (Figure ). polymerised bow-tie shape. Microscope images of (e) the intersection between two polymer tracks and (f) a cross-section from the end, which appears hollow. Photographs of the template 'UofG' (g) immediately after polymerisation and (h) after solvent washing and rearrangement, with the stencil text above.