To prepare chiral nanostructures coated with bioactive molecules, a side-chain amino acid containing macromolecular chain transfer agent (macroCTA), poly(Boc-L-alanine methacryloyloxyethyl ester) (PBLAEMA), has been used as the steric stabilizer for the reversible addition-fragmentation chain transfer (RAFT) mediated dispersion polymerization of benzyl methacrylate (BzMA) in methanol at 65°C. Gel permeation chromatography (GPC) analysis confirmed an efficient and well-controlled block copolymerization. A full spectrum of morphologies spanning spherical micelles, worm like micelles, fibres and vesicles could be attained by tuning (i) the length of the solvophobic block and (ii) the total solid content at which the block copolymerization is performed. Interestingly, a purely fibre phase morphology formed a thermoresponsive gel at room temperature above a critical fibre entanglement concentration, which underwent degelation upon heating because of the morphological transformation from anisotropic fibre to isotropic sphere. In actual fact, twisted nano-fibres have been formed through the hierarchical selfassembling of polymerization induced self-assembly (PISA) generated macromolecules in the gel state.Circular dichroism (CD) spectroscopy was used to elucidate chiroptical properties. Additionally, a high demanding wrinkle surface has been constructed preliminarily from this copolymer dispersion solution.Successful Boc-group expulsion facilitates the disassembly of vesicles to either worms or spheres with an appreciable cationic character below pH 7.0 as revealed by aqueous electrophoresis studies. Though the creation of nano-objects through PISA is well-known, fabricating chiral nanostructures with reactive handles and their hierarchical self-organization to have functional architectures is a less explored area. In this present work we were able to hybridize PISA, chirality and hierarchical self-assembling. † Electronic supplementary information (ESI) available: GPC chromatograms, CD spectra, 1 H NMR spectrum and DLS size distributions of various block copolymers. See

This work reports design and synthesis of side chain amino acid based cross-linked polymeric gels, able to switch over from organogel to hydrogel by a simple deprotection reaction and showing superabsorbancy in water. Amino acid based methacrylate monomers, tert-butoxycarbonyl (Boc)-l/d-alanine methacryloyloxyethyl ester (Boc-l/d-Ala-HEMA), have been polymerized in the presence of a cross-linker via conventional free radical polymerization (FRP) and the reversible addition-fragmentation chain transfer (RAFT) technique for the synthesis of cross-linked polymer gels. The swelling behaviors of these organogels are investigated in organic solvents, and they behave as superabsorbent materials for organic solvents such as dichloromethane, acetone, tetrahydrofuran, etc. Swollen cross-linked polymer gels release the absorbed organic solvent rapidly. After Boc group deprotection from the pendant alanine moiety, the organogels transform to the hydrogels due to the formation of side chain ammonium (-NH3(+)) groups, and these hydrogels showed a significantly high swelling ratio (∼560 times than their dry volumes) in water. The morphology of organogels and hydrogels is studied by field emission scanning electron microscopy (FE-SEM). Amino acid based cross-linked gels could find applications as absorbents for oil spilled on water as well as superabsorbent hydrogels.

Developing a simple and cheap analytical method for the selective detection and quantitative separation of toxic ions present in aqueous media is the biggest challenge faced by the chemosensing research community. Here, a 5,5difluoro-1,3,7,9-tetramethyl-10-phenyl-5H-dipyrrolo-diazaborinine-derived water-soluble polymer integrated with thiosemicarbazone units was rationally designed and synthesized for the simultaneous detection and separation of Hg(II) ions in pure aqueous solution. The water-soluble polymer scaffold poly(N,N′-dimethyl acrylamide-co-5,5-difluoro-1,3,7,9-tetramethyl-10-phenyl-5H-dipyrrolo-diazaborinine-2-carbaldehyde) was synthesized by reversible addition−fragmentation chain transfer polymerization, followed by post-polymerization modification with thiosemicarbazide, leading to the formation of the target probe, P1. The nonemitting P1 exhibited bright yellow emission upon exposure to Hg(II) ions, with a limit of detection as low as 0.37 μM. This turn-on emission behavior triggered by Hg(II) ions might originate from the suppression of isomerization around the CN bond of the thiosemicarbazone moiety caused by the formation of a coordination complex between P1 and Hg(II) ions. In addition, P1 displayed excellent selectivity toward Hg(II) ions over other metal cations. Finally, the selective removal of Hg(II) ions from an aqueous solution containing various metal ions was achieved by precipitation, which is probably caused by the fact that coordination complexes whereby Hg(II) ions acted as bridgeheads between P1 molecules had formed.

This work demonstrates the successful application of dynamic covalent chemistry for the construction of self-healing gels from side-chain primary amine leucine pendant diblock copolymers of polyisobutylene (PIB) ((P(H2N-Leu-HEMA)-b-PIB)) in the presence of PIB based dialdehyde functionalized cross-linker (HOC-PIB-CHO) through imine (-HC═N-) bond formation without aiding any external stimuli. Gels were synthesized in 1,4-dioxane at room temperature at varied wt % of gelator concentration, [H2N]/[CHO] ratios and molecular weight of the block segments. The mechanical property of gels was examined by rheological measurements. We observed higher value of storage modulus (G') than the loss modulus (G″) within the linearity limits of deformation, indicating the rheological behavior in the gel is dominated by an elastic property rather than a viscous property. The G' values significantly depend upon the extent of cross-linking in the gel network. To establish self-healing property of the gels, rheology analysis through step-strain measurements (strain = 0.1 to 200%) at 25 °C was performed. The polymeric gel network shows reversible sol-gel transition for several cycles by adjusting the pH of the medium with the help of hydrochloric acid (HCl) and triethylamine (Et3N) triggers. FT-IR spectroscopy established formation of imine bonds in the gel network and these gels showed poor swelling behavior in various organic solvents because of the small interstitial porosity, confirmed by field emission-scanning electron microscopy (FE-SEM).

A water-soluble BODIPY-containing polymeric chemosensor was synthesized for the selective colorimetric and turn-on fluorimetric detection of Hg2+ and HSO4− ions, respectively, in 100% aqueous media at physiological pH.