This article describes a well-designed supramolecular assembly of a classical polyurethane scaffold containing pendant n-type semiconducting naphthalene− diimide (NDI) chromophores and consequences on excited state dynamics and charge carrier mobilities. A polycondensation reaction between hexamethylene−diisocyanate and a NDI-containing diol in the presence of a chiral "monofunctional impurity" produced the desired polymer (P1) with a predictable degree of polymerization and end-capping by chiral units. In aliphatic hydrocarbons, such as methylcyclohexane (MCH), P1 adopts a folded conformation with appreciably high thermal stability by intrachain H-bonding among the urethane groups as established by solvent, concentration and temperature-dependent FT-IR and 1 H NMR spectroscopy and small angle XRD studies. Folded structure can be further ascertained by the pronounced Cotton effect in MCH owing to the chiral induction by the so-called "sergeant and soldiers" principle from the asymmetric units located only at the chain ends. Intrachain folding facilitates spatial organization of the pendant groups leading to π−π interaction among the neighboring NDI chromophores attached to the same polymer chain resulting in intense green emission in MCH in sharp contrast to the blue-emitting unfolded polymer in benign solvents such as CHCl 3 or THF. P1 in the folded state resembles the organization of classical bolaamphiphile and thus adopts a polymersome-like spherical structure. Upon aging macroscopic gelation can be observed owing to the fusion of these discrete spherical assemblies generating micrometer long multiwall nanotubes as noticed in HRTEM, AFM and fluorescence microscopy images. Transient absorption spectroscopy studies indicate formation of NDI radical anions in the excited state both in unfolded and folded conformation which contribute to their intrinsic electron transporting (n-type) property, as revealed by flash-photolysis timeresolved microwave conductivity (FP-TRMC). Significantly larger electron mobility and longer lifetime of charge carriers were observed for the folded tubular assembly than those for unfolded polymer, likely due to a better delocalization of the chargecarriers in the integrated tubular assembly consisting of stacked NDI arrays inside the multilayer wall.

We have reported synthesis and vesicular assembly of a novel amphiphilic polyurethane with hydrophobic backbone and hydrophilic pendant carboxylic acid groups which were periodically grafted to the backbone via a tertiary amine group. In aqueous medium the polymer chain adopted a folded conformation which was stabilized by intrachain H-bonding among the urethane groups. Such a model was supported by concentration and solvent-dependent FT-IR, powder XRD, and urea-mediated "denaturation" experiments. Folded polymer chains further formed vesicular assembly which was probed by dynamic light scattering, TEM, AFM, SEM, and fluorescence microscopic studies, and dye encapsulation experiments. pH-dependent DLS and fluorescence microscopic studies revealed stable polymersome in entire tested pH window of 3.5-11.0. Zeta potential measurements showed a negatively charged surface in basic pH while a charge-neutral surface in neutral and acidic pH. MTT assay with CHO cell line indicated good cell viability.

Sequence-defined poly(N-substituted urethanes) were synthesized via a solid-phase iterative protocol including two successive orthogonal coupling steps: the formation of an activated carbonate and its chemoselective reaction with the secondary amine group of amino alcohol building blocks. This simple method was used to write binary information on the formed polymers using four-coded molecules, 2-(methylamino)ethanol, 2-(ethylamino)ethanol, 2-(propylamino)ethanol, and 2-(butylamino)ethanol, symbolizing binary dyads 00, 01, 10, and 11, respectively. The method is fast and allows synthesis of uniform oligomers and polymers with controlled lengths (4-mer to 28-mer) and digital information sequences. Furthermore, the coded poly(N-substituted urethanes) were easily characterized by electrospray mass spectrometry and decoded by tandem mass spectrometry. Overall, these digital macromolecules offer interesting advantages over conventional sequence-coded polyurethanes, i.e., synthesis of longer chains, reduced synthesis times, and better solubility and processing in common organic solvents.

This article reports the antimicrobial activity of two segmented amphiphilic polyurethanes, PU-1 and PU-2, containing a primary or secondary amine group, respectively. In acidic water, intrachain H-bonding among the urethanes followed by hierarchical assembly resulted in the formation of capsules (D h = 120 ± 20 and 100 ± 17 nm for PU-1 and PU-2, respectively) with a highly positive surface charge. They showed selective interactions with bacterial cell mimicking liposomes over mammalian cell mimicking liposomes with favorable enthalpy and entropy contributions, which was attributed to the electrostatic interaction and hydrophobic effect. Antimicrobial studies with Escherichia coli revealed very low minimum inhibitory concentration (MIC) values of 7.8 and 15.6 μg/mL for PU-1 and PU-2, respectively, indicating their ability to efficiently kill Gram-negative bacteria. Killing of Gram-positive Staphylococcus aureus was noticed only at C = 500 μg/mL, indicating unprecedented selectivity for E. coli, which was further confirmed by scanning electron microscopy (SEM) studies. Hemolysis assay revealed HC50 values of 453 and 847 μg/mL for PU-1 and PU-2, respectively, which were >50 times higher than their respective MIC values, thus making them attractive antimicrobial materials. Ortho-nitrophenyl-β-galactoside (ONPG) assay and live–dead fluorescence assay confirmed that for both the polymers, a membrane disruption pathway was operative for wrapping of the bacterial membrane, similar to what was proposed for antimicrobial peptides. SEM images of polymer-treated E. coli bacteria helped in visualization of the pore formation and the disrupted membrane structure.

The degradation and repair of uniform sequence‐defined poly(N‐substituted urethane)s was studied. Polymers containing an ω‐OH end‐group and only ethyl carbamate main‐chain repeat units rapidly degrade in NaOH solution through an ω→α depolymerization mechanism with no apparent sign of random chain cleavage. The degradation mechanism is not notably affected by the nature of the side‐chain N‐substituents and took place for all studied sequences. On the other hand, depolymerization is significantly influenced by the molecular structure of the main‐chain repeat units. For instance, hexyl carbamate main‐chain motifs block unzipping and can therefore be used to control the degradation of specific sequence sections. Interestingly, the partially degraded polymers can also be repaired; for example by using a combination of N,N′‐disuccinimidyl carbonate with a secondary amine building‐block. Overall, these findings open up interesting new avenues for chain‐healing and sequence editing.

Unique H-bonding motifs of 1,3-dihydroxyl derivatives involving simultaneous intra- and inter-molecular H-bonding results in extended organization of pendant chromophores with a spatial distance suitable for π-π interaction. A preformed assembly with appended acceptor units exhibits host-guest interaction with specific donors by charge-transfer complex formation.

Sequence‐defined synthetic polymers have recently emerged as an attractive medium to store information at the molecular level, where comonomers of the chains are defined as letters of an alphabet. The main read‐out methodology employed to retrieve such molecularly encoded information is tandem mass spectrometry (MS/MS), but a major current limitation remains the low storage capacity of readable chains. Ordering short oligomers at discrete locations onto surfaces to compose long messages is an attractive alternative to the difficult synthesis of long coded polymers. Yet, such surface storage requires a reliable sampling technique to be coupled on‐line with MS/MS. Because it combines fast surface extraction with efficient analyte ionization in ambient conditions, desorption electrospray ionization (DESI) is shown here to be perfectly suited to envisage bidimensional data storage. The present study demonstrates performances of DESI‐MS/MS at mapping oligomers used to write letters of a word, extracting digital labels from materials tagged for anticounterfeiting purposes, and imaging text written with coded polymeric inks.

The DNA-guided assembly of biohybrid sequence-defined poly(phosphodiester)s was investigated. These polymers contain long non-natural segments covalently connected to single-stranded DNA sequences. These biohybrid structures were synthesized by automated phosphoramidite chemistry using both nucleoside and abiological phosphoramidite monomers. Using complementary DNA strands, the precursors were then assembled in aqueous buffer into linear or star-like superstructures. For instance, linear supramolecules containing 442 (352 non-natural monomers connected by three double-stranded DNA bridges of 15 base pairs) and 990 monomers (720 non-natural monomers connected by nine double-stranded DNA bridges of 15 base pairs) were prepared. A four-arm star structure containing 488 monomers (352 non-natural monomers connected by a four-arm junction of 68 base pairs) was also achieved. The formed supramolecules were characterized by electrophoresis, UV spectroscopy, and atomic force microscopy. All these techniques evidenced the formation of the expected supramolecules, although some defects were also evidenced. These results open up interesting avenues for the design of two-dimensional (2D) and three-dimensional (3D) constructs based on informational poly(phosphodiester)s.