Double hydrophilic copolymers - synthetic approaches, architectural variety, and current application fields.

Solubility and functionality of polymeric materials are essential properties determining their role in any application. In that regard, double hydrophilic copolymers (DHC) are typically constructed from two chemically dissimilar but water-soluble building blocks. During the past decades, these materials have been intensely developed and utilised as, e.g., matrices for the design of multifunctional hybrid materials, in drug carriers and gene delivery, as nanoreactors, or as sensors. This is predominantly due to almost unlimited possibilities to precisely tune DHC composition and topology, their solution behavior, e.g., stimuli-response, and potential interactions with small molecules, ions and (nanoparticle) surfaces. In this contribution we want to highlight that this class of polymers has experienced tremendous progress regarding synthesis, architectural variety, and the possibility to combine response to different stimuli within one material. Especially the implementation of DHCs as versatile building blocks in hybrid materials expanded the range of water-based applications during the last two decades, which now includes also photocatalysis, sensing, and 3D inkjet printing of hydrogels, definitely going beyond already well-established utilisation in biomedicine or as templates.

Triple-Responsive Polyampholytic Graft Copolymers as Smart Sensors with Varying Output.

Three triggers result in two measurable outputs from polymeric sensors: multiresponsive polyampholytic graft copolymers respond to pH-value and temperature, as well as the type and concentration of metal cations and therefore, allow the transformation of external triggers into simply measurable outputs (cloud point temperature (TCP ) and surface plasmon resonance (SPR) of encapsulated silver nanoparticles). The synthesis relies on poly(dehydroalanine) (PDha) as the reactive backbone and gives straightforward access to materials with tunable composition and output. In particular, a rather high sensitivity toward the presence of Cu2+ , Co2+ , and Pb2+ metal cations is found.

1,7,9,10-Tetrasubstituted PMIs Accessible through Decarboxylative Bromination: Synthesis, Characterization, Photophysical Studies, and Hydrogen Evolution Catalysis.

In this work, we present a new synthetic strategy for fourfold-substituted perylene monoimides via tetrabrominated perylene monoanhydrides. X-ray diffraction analysis unveiled the intramolecular stacking orientation between the substituents and semicircular packing behavior. We observed the remarkable influence of the substituent on the longevity and nature of the excited state upon visible light excitation. In the presence of poly(dehydroalanine)-graft-poly(ethylene glycol) graft copolymers as solubilizing template, the chromophores are capable of sensitizing [Mo3 S13 ]2- clusters in aqueous solution for stable visible light driven hydrogen evolution over three days.

Rational Design of Amphiphilic Diblock Copolymer/MWCNT Surface Modifiers and Their Application for Direct Electrochemical Sensing of DNA.

We demonstrate the application of amphiphilic ionic poly(n-butylmethacrylate)-block- poly(2-(dimethylamino)ethyl methacrylate) diblock copolymers (PnBMA40-b-PDMAEMA40, PnBMA40-b-PDMAEMA120, PnBMA70-b-PDMAEMA120) for dispersing multiwalled carbon nanotubes (MWCNTs) in aqueous media, a subsequent efficient surface modification of screen-printed electrodes (SPEs), and the application of the modified SPEs for DNA electrochemistry. Stable and fine aqueous dispersions of MWCNTs were obtained with PnBMAx-b-PDMAEMAy diblock copolymers, regardless of the structure of the copolymer and the amount of MWCNTs in the dispersions. The effect of the diblock copolymer structure was important when the dispersions of MWCNTs were deposited as modifying layers on surfaces of SPEs, resulting in considerable increases of the electroactive surface areas and great acceleration of the electron transfer rate. The SPE/(PnBMAx-b-PDMAEMAy + MWCNT) constructs were further exploited for direct electrochemical oxidation of the guanine (G) and adenine (A) residues in a model salmon sperm double-stranded DNA (dsDNA). Two well-defined irreversible oxidation peaks were observed at about +600 and +900 mV, corresponding to the electrochemical oxidation of G and A residues, respectively. A multi-parametric optimization of dsDNA electrochemistry enables one to get the limits of detection (LOD) as low as 5 µg/mL (0.25 µM) and 1 µg/mL (0.05 µM) for G and A residues, respectively. The achieved sensitivity of DNA assay enables quantification of the A and G residues of dsDNA in the presence of human serum and DNA in isolated human leukocytes.