01575nas a2200193 4500008004100000022001400041245016200055210006900217260000900286300001600295490000700311520081500318100002201133700001901155700002401174700002601198700002801224856012901252 2023 eng d a0022-326300aCarbamate-Protected (BOC and O-NB) 2-Aminopyrimidinedione-based janus G-C nucleobase motifs as building blocks for supramolecular assembly and smart polymers0 aCarbamateProtected BOC and ONB 2Aminopyrimidinedionebased janus  cOCT  a14953-149590 v883 a

In this paper, we report ``carbamate protected'' 2-aminopyrimidinedione-based Janus G-C nucleobases (2-APD Janus G-C nucleobases) featuring polymerizable groups and self-complementary triple H-bonding motifs DDA and AAD as building blocks for developing smart polymers and self-healing materials. The carbamate-masked H-bonding motif, cleavable under acidic (BOC group) or photocleavable (O-nitrobenzyl group) conditions, would facilitate the synthesis of smart polymers by alleviating aggregation during polymerization which in turn would exclude self-assembly-assisted solubility issues. Ready accessibility in excellent yields coupled with the possibility for facile introduction of polymerizable groups would make these building blocks excellent candidates for diverse polymerization applications.

1 aSingh, Dharmendra1 aLakshmi, Durga1 aMeena, Chhuttan, L.1 aKrishna, Gamidi, Rama1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/carbamate-protected-boc-and-o-nb-2-aminopyrimidinedione-based-janus-g-c-nucleobase-motifs02410nas a2200289 4500008004100000022001400041245010600055210006900161260000900230300001200239490000700251520145900258653001901717653001301736653002201749653002601771653001801797100001801815700002001833700003001853700001901883700002301902700001701925700002601942700002701968856012501995 2026 eng d a1060-132500aDesign, synthesis, and adhesive performance evaluation of DOPA-Functionalized polyurethane elastomers0 aDesign synthesis and adhesive performance evaluation of DOPAFunc cJUN  a482-4920 v633 a

Functional polyurethane (PU) hot-melt adhesives were developed through the incorporation of a dopamine-derived chain extender (DADO) into thermoplastic PUs. The DADO monomer was synthesized via a four-step route and successfully integrated into the PU backbone using a one-pot, two-step polymerization involving polycaprolactone-diol and 4,4 `-methylenebis(phenyl isocyanate). Spectral analyses confirmed the formation of urethane linkages and the effective incorporation of catechol moieties. Monomodal molecular weight distributions were obtained through size-exclusion chromatography with Mn ranging from 12,000 to 17,000 g/mol. Thermal analyses demonstrated two-step decomposition behavior and a progressive increase in glass transition temperature with increasing DADO content. Mechanical testing revealed that there was substantial improvement in the tensile strength of these materials from 1.34 MPa for unmodified PU (PU-0) to 14.3 MPa for PU-10. Adhesion performance exhibited a similar trend, with PU-10 attaining the highest lap-shear strength of 3.92 +/- 0.19 MPa on the Al substrate. PU-10 exhibited the highest lap-shear strength of 3.92 +/- 0.19 MPa on aluminum and superior underwater stability with a value of 2.78 +/- 0.47 MPa compared to other formulations. Overall, controlled incorporation of DADO significantly enhances properties, and PU-10 represents the optimal formulation for high-performance hot-melt PU adhesives.

10achain extender10adopamine10ahot-melt adhesive10apolycaprolactone diol10apolyurethanes1 aDavis, Disiya1 aAlam, Md, Shafi1 aBindu, Bhadra, Purushotha1 aLakshmi, Durga1 aMuhammed, Hasin, N1 aTorris, Arun1 aAmbade, Ashootosh, V.1 aNair, Kiran, Sukumaran uhttps://library.ncl.res.in/content/design-synthesis-and-adhesive-performance-evaluation-dopa-functionalized-polyurethane02417nas a2200241 4500008004100000022001400041245010900055210006900164260000800233300001400241490000700255520158900262100001901851700002301870700001901893700002001912700002101932700001701953700001901970700002801989700002702017856013102044 2026 eng d a0897-475600aDynamic janus hydrogen bond mimicry unlocks tough, flexible supramolecular elastomers for strain sensing0 aDynamic janus hydrogen bond mimicry unlocks tough flexible supra cMAR a2699-27110 v383 a

Flexible and wearable electronics demand stretchable sensors with polymer elastomers as key matrixes for mechanical flexibility and durability. However, despite their excellent elasticity, their limited mechanical strength remains a challenge. To address this limitation, in this study, we report the rational design of supramolecular polyurethane elastomers (SPUs) incorporating nucleobase-inspired aminopyrimidinedione with DDA-AAD (G-C mimic) reversible triple hydrogen bonds. This dual-domain architecture gives rise to a durable supramolecular network with enhanced mechanical properties, yielding elastomers that are soft, stretchable, and tough. By tuning of the density of dynamic cross-links, mechanical properties were systematically modulated. SPU-0.5 exhibited a maximum tensile strength of 16.14 MPa, representing a 67-fold strength enhancement over that of SPU-0. Although increasing the aminopyrimidinedione (APD) content reduced elongation, SPU-0.2 retained a high elongation of 1060% and showed the lowest residual strain during cyclic tests. To be of great interest, the activation energy increased with increasing hydrogen bonding content up to SPU-0.1, whereas beyond SPU-0.2 it decreased, likely due to extensive hydrogen bond formation. Furthermore, SPU-0.2-SP, a conductive variant, demonstrated a promising strain-sensing performance even after hundreds of cycles. Overall, the insights gained from this study advance the development of intelligent soft materials and lay the groundwork for next-generation flexible and wearable electronic devices.

1 aLakshmi, Durga1 aWagh, Mahendra, A.1 aSharma, Aakash1 aAlam, Md, Shafi1 aSelvan, Muthamil1 aTorris, Arun1 aMondal, Titash1 aSanjayan, Gangadhar, J.1 aNair, Kiran, Sukumaran uhttps://library.ncl.res.in/content/dynamic-janus-hydrogen-bond-mimicry-unlocks-tough-flexible-supramolecular-elastomers-strain