Nezha Badi

Peptoids (N-substituted glycines) are a promising material platform for next-generation biomedical applications, as control over monomer sequence enables the design of functional materials with defined morphologies, which in turn allow for precise interactions with biological targets. Traditional synthetic approaches for peptoids suffer from a tradeoff between scalability and synthetic versatility. Solid-phase submonomer synthesis methods facilitate sequence specificity and side chain diversity but require large reagent excesses and remain challenging to monitor. Meanwhile, solution-phase methods have limited sequence definition and intensive purification requirements. Here, we present a Rink amide soluble support to synthesize peptoids via the submonomer method using reduced reagent excesses and a simple workup procedure while supporting iterative synthesis of diverse linear and cyclic peptoid architectures. This solution-phase approach allows for real-time reaction monitoring via ReactIR and mass spectrometry. The Rink amide soluble support is a flexible platform that bridges the gap between solid- and solution-phase methods and can simplify synthesis in future peptoid studies.

Liquid crystals (LCs) are a class of materials that combine molecular order and fluidity, making them crucial for technologies from displays to sensors. However, polymeric LC materials typically lack molecular precision, limiting systematic control over their phase behavior. Here, we report a modular synthetic strategy to prepare amphiphilic columnar liquid crystals based on hydrophobic di- and trialkylated galloyl cores attached to a sequence-defined polar oligomer grown by a thiolactone-based iterative protocol. This approach enables independent variation of (i) polar monomer type (e.g., hydroxyethyl acrylate and N,N-dimethylacrylamide), (ii) oligomer length (from 1-mer to tetramer), and (iii) core topology (two or three C18 chains). Differential scanning calorimetry, polarized optical microscopy, and X-ray scattering show that the number of hydrophobic C18 chains on the aromatic core is the dominant parameter governing mesophase stability. Derivatives with three C18 chains exhibit higher melting and isotropization temperatures and more pronounced transitions from lamellar crystals to hexagonally packed columnar mesophases than their two C18 analogues. The chemistry and length of the sequence-defined polar block further tune crystallization and mesophase behavior, i.e. hydrogen-bonding heads increase thermal stability, whereas bulkier PEG-like heads reduce crystallinity and can destabilize mesophases. Increasing oligomer length reduces crystallization enthalpies and can introduce competing liquid-crystalline states. These results demonstrate that the liquid crystalline behavior can be encoded at the molecular level, providing a basis for designing responsive and sequence-programmed LC materials.

Sequence-defined oligomers offer programmable molecular architectures with potential in data storage, authentication, and anticounterfeiting. However, their deployment in real-world materials has been constrained by their low scale, limited thermal resilience and the need for specialized analytical methods. Here we introduce a molecular tagging strategy based on abiotic sequence-defined oligoamides incorporated at ultralow concentrations ( < 0.05 wt%) that endure the thermal and chemical conditions of industrial polymer processing. A four-monomer alphabet derived from unnatural amino acids enables the construction of digital molecular sequences that permit a first optical identification through ultraviolet absorption and/or fluorescence from chromophoric terminal groups. Sequence authentication, implemented via an automated Python-scripted readout strategy from tandem mass spectra, enables rapid and reproducible molecular code identification. Comparative studies of secondary and tertiary amide backbones reveal structure-stability correlations that govern the design of thermally robust taggants. The oligoamides retain structural integrity within both commodity thermoplastics and thermosets, surviving extrusion (up to 270 °C) and curing processes while remaining fully decodable. This approach establishes a versatile platform for secure molecular identification and traceability across several types of industrial plastic materials.

Sequence-defined macromolecules (SDMs) offer tremendous promise for critical applications like data storage, optoelectronics, or biomimetics, but their synthesis remains particularly challenging. A generic SDM synthesis strategy is reported now using a support-free orthogonal approach starting from single monomers to produce SDMs. The procedure does not require any support, protection, or deprotection steps, nor does it require solvent switches. Crucially, each reaction step is followed by purification using solvent-resistant nanofiltration to ensure product retention from the reaction mixture with the complete removal of impurities (excess reagents, catalyst, byproducts). The sharp molecular weight resolution of well-tuned epoxy-based membranes renders this strategy highly efficient and versatile, as proven here by applying varying reactions, monomer types, and sizes to prepare two different sequence-defined conjugated macromolecules (SDCMs). Demonstrating the effectiveness of these membrane separations to purify SDCMs across very diverse conditions thus highlights the transformative potential of advanced membrane technology for SDM synthesis. Overall, a robust foundation is provided for advancing SDM development from single monomers to complex, high-purity oligomers.

This study explores a newly identified transamidation exchange in the β-amino amide dynamic covalent chemistry and the chemical recycling of β-amino amide-derived covalent adaptable networks.

This study presents a scalable, solution-phase protocol for the synthesis of monodisperse oligoamides with nylon-4, nylon-6 and hybrid nylon-4/6 backbones, enabled by a group assisted purification strategy. For this, unnatural amino acid monomers are iteratively coupled onto a phosphonate-functional soluble support, yielding uniform oligomers bearing orthogonal functional end groups that allow their solid-state polycondensation (SSP). Pure monodisperse oligomer precursors of nylon-4 exhibits thermal limitations due to their low ceiling temperature, resulting in low molecular weight products after SSP. In contrast, incorporation of strategically positioned nylon-6 units effectively suppress backbiting and facilitates efficient SSP, producing well-defined nylon-4/6 copolymers. This unique design approach offers unprecedented control over the polyamide microstructure and establishes a versatile route toward polyamide synthesis with potential for customizing material properties.

Sequence-defined oligomers offer programmable molecular architectures with potential in data storage, authentication, and anticounterfeiting. However, their deployment in real-world materials has been constrained by their low scale, limited thermal resilience and the need for specialized analytical methods. Here we introduce a molecular tagging strategy based on abiotic sequence-defined oligoamides incorporated at ultralow concentrations (< 0.05 wt%) that endure the thermal and chemical conditions of industrial polymer processing. A four-monomer alphabet derived from unnatural amino acids enables the construction of digital molecular sequences that permit a first optical identification through ultraviolet absorption and/or fluorescence from chromophoric terminal groups. Sequence authentication, implemented via an automated Python-scripted readout strategy from tandem mass spectra, enables rapid and reproducible molecular code identification. Comparative studies of secondary and tertiary amide backbones reveal structure-stability correlations that govern the design of thermally robust taggants. The oligoamides retain structural integrity within both commodity thermoplastics and thermosets, surviving extrusion (up to 270°C) and curing processes while remaining fully decodable. This approach establishes a versatile platform for secure molecular identification and traceability across several types of industrial plastic materials.