As the most important skeletal component in plants, the polysaccharide cellulose is an almost inexhaustible polymeric raw material with fascinating structure and properties. Formed by the repeated connection of D-glucose building blocks, the highly functionalized, linear stiff-chain homopolymer is characterized by its hydrophilicity, chirality, biodegradability, broad chemical modifying capacity, and its formation of versatile semicrystalline fiber morphologies. In view of the considerable increase in interdisciplinary cellulose research and product development over the past decade worldwide, this paper assembles the current knowledge in the structure and chemistry of cellulose, and in the development of innovative cellulose esters and ethers for coatings, films, membranes, building materials, drilling techniques, pharmaceuticals, and foodstuffs. New frontiers, including environmentally friendly cellulose fiber technologies, bacterial cellulose biomaterials, and in-vitro syntheses of cellulose are highlighted together with future aims, strategies, and perspectives of cellulose research and its applications.

Cellulose: Fascinating Biopolymer and Sustainable Raw Material

Core/Shell Nanoparticles: Classes, Properties, Synthesis Mechanisms, Characterization, and Applications

About Supramolecular Assemblies of π-Conjugated Systems

Transmission electron microscopy and electron diffraction are used to study the changes in morphology of composite films of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) in bulk heterojunction solar cells. Thermal annealing produces and stabilizes a nanoscale interpenetrating network with crystalline order for both components. P3HT forms long, thin conducting nanowires in a rather homogeneous, nanocrystalline PCBM film. Both the improved crystalline nature of films and increased but controlled demixing between the two constitutes therein after annealing explains the considerable increase of the power conversion efficiency observed in these devices.

Nanoscale Morphology of High-Performance Polymer Solar Cells

Functional π-Gelators and Their Applications

Solvent-induced aggregation of regioregular head-to-tail poly(3-alkylthiophene)s (PATs) have been studied by means of AFM and UV−vis spectroscopy. In hexane, which is a good solvent for alkyl side chains but poor for polythiophene backbones, PAT molecules undergo ordered main-chain collapse driven by solvophobic interaction. Well-pronounced concentration-independent red shift of λmax and good resolved fine vibronic structure in the electronic absorption spectra observed upon addition of hexane indicate that planarization occurs on the single-molecule level. A helical conformation of the man chain of PATs with 12 thiophene rings per each helical turn has been proposed. At the higher concentration of PATs the collapsed molecules undergo unexpected one-dimensional aggregation. Length of the particles varies from several nanometers to several hundreds nanometers and can be easily adjusted by the solvent composition or concentration of PATs.

One-Dimensional Aggregation of Regioregular Polyalkylthiophenes

High clay content nanocomposite hydrogels with surprising mechanical strength and interesting deswelling kinetics

A series of high clay content Laponite XLS/ polyacrylamide (PAAm) nanocomposite hydrogels (S-M gels) with excellent resilience, low elastic hysteresis, and ultrahigh elongation, have been successfully synthesized. Based on our results, it is concluded that the mechanical properties ofnanocomposite hydrogels probably depend to a great extent on the hydrophilicity and flexibility of the macromolecules. More, over, his found that the transparency during the in-situ polymrization of S-M gels does not change, which is quite different from clay/poly(N-isopropyl-acrylamide) nanocomposite hydrogels.

A Novel Highly Resilient Nanocomposite Hydrogel with Low Hysteresis and Ultrahigh Elongation

Self-assembling adhesion promoters for corrosion resistant metal polymer interfaces

In the present paper, we report the preparation of hybrid temperature-sensitive microgels which include magnetite nanoparticles in their structure. Polymeric microgels have been prepared by surfactant-free emulsion copolymerization of acetoacetoxyethyl methacrylate (AAEM) and N-vinylcaprolactam (VCL) in water with a water-soluble azo-initiator. The obtained microgels possess a low critical solution temperature (LCST) in water solutions, with a rapid decrease of the particle size being observed at elevated temperatures. Magnetite was deposited directly into microgels, leading to the formation of composite particles which combine both temperature-sensitive and magnetic properties. The influence of magnetite load on microgel size, morphology, swelling-deswelling behavior, and stability is discussed.

Hans-Juergen P. Adler

Papers

One-Dimensional Aggregation of Regioregular Polyalkylthiophenes

High clay content nanocomposite hydrogels with surprising mechanical strength and interesting deswelling kinetics

A Novel Highly Resilient Nanocomposite Hydrogel with Low Hysteresis and Ultrahigh Elongation

Self-assembling adhesion promoters for corrosion resistant metal polymer interfaces

Temperature-Sensitive Hybrid Microgels with Magnetic Properties