No abstract

Block copolymers containing poly(phenylene oxide) (PPO) and poly(vinyl benzyl phosphonic acid) segments are synthesized via atom transfer radical polymerization (ATRP). Monofunctional PPO blocks are converted into ATRP active macroinitiators, which are then used to polymerize a diethyl p -vinylbenzyl phosphonate monomer in order to obtain phosphonated block copolymers bearing pendent phosphonic ester groups. Poly(phenylene oxide-b -vinyl benzyl phosphonic ester) block copolymers are hydrolyzed to corresponding acid derivatives to investigate their proton conductivity. The effect of the relative humidity (RH) is investigated. The proton conductivity at 50% RH and one bar of vapor pressure approaches 0.01 S cm − 1 .

Dissipative particle dynamics simulations were performed on phosphonic acid-functionalized copolymer melt. This copolymer consists of poly(ether-ether-ketone) and poly(p-vinylbenzylphosphonic acid) blocks. Three different mapping schemes were implemented to obtain the morphology in different length scales. The morphology obtained from the simulation of the copolymer when mapped in correspondence to experimentally obtained polymer showed a similar morphology to that obtained from scanning tunneling and atomic force microscopy. The simulations show that the poly(ether-ether-ketone) blocks aggregate in small clusters embedded by poly(p-vinylbenzylphosphonic acid) blocks. Two further mapping schemes were undertaken to elucidate the phase behavior in p-vinylbenzylphosphonic acid blocks in molecular scale. The results obtained from the simulations as well as the new identified morphologies provide useful information for synthesizing a new set of polymers which could be important to show promise for fuel cell application.

In a simplistic way, 2D black phosphorus (BP) nanosheets are exfoliated in a polar solvent at room temperature. Afterward, as-obtained BP or phosphorene nanosheets are passivated and encapsulated simultaneously by using an artificial polypeptide polymer having an ability to form micelles. In first step, thin layers of BP nanosheets were obtained by sonication. Next, helical copolymer based on polyethylene glycol and poly(phenyl isocyanidepeptide) blocks is then allowed to blend with the suspension of phosphorene nanosheets for their inclusion in micelles. The size of nanosheets is reduced after their encapsulation inside the polymeric micelle. The copolymer based on polypeptide is also supposed to improve biocompatibility. The microstructures of these 2D nanosheets are investigated by transmission electron microscopy. The transmission electron microscopy results show that the BP nanosheets are included within the helical cavity of the copolymer indicating the hydrophobic nature of the nanosheets. Atomic force microscopy images indicate the formation of smooth and flat nanosheets. Photoluminescence (PL) experiments suggest that the emission from polymer micelles is quenched after nanosheets are embedded within the polymer helical matrix. For polymer micelles, the disappearance of emission proves that electron transfer (ET) occurs between the BP nanosheets and polymer helix. Even after encapsulation, the BP nanosheets are sensitive to light and emits with a sharp signal that shifts slightly toward the blue region. This single step approach for passivation and encapsulation of BP nanosheets provides new solution for protecting the BP nanosheets from oxidation and fabrication without compromising the electronic properties. After fabrication, these 2D active hybrids can be integrated in a device for sensing applications. These 2D nanomaterials can also be introduced in an infected tissue for imaging or delivering a drug particulate.

Well‐defined copolymers synthesized by combining poly(ethylene glycol) (PEG) and amino acid based building blocks are investigated with regard to their helical rigidity and self‐assembly. Optical active block copolymers reported here are designed to have a pendant amino acid and polymerizable group, that is, isonitrile in order to induce helix formation and reduce the mobility of polymer chains by forming a hydrogen bond network so that a helix with reasonable rigidity can be obtained. Due to the amphiphilicity and a relatively shorter PEG as a coil, these polymers form micelles as observed under transmission electron microscopy in which copolymers PEG108‐b‐PPIC764 and PEG108‐b‐PPIC1020 appear to be evolving into nanoparticles with a size distribution of 100–200 nm. Circular dichroism spectroscopy is employed to study the nature of the helix and its rigidity. The folding and unfolding of polymer helix as a result of the ability of a selective solvent to form/disrupt hydrogen bonds with the peptide linkage is also discussed to highlight the responsive nature of the polymer.