Zipper and layer-by-layer assemblies of artificial photosystems analyzed by combining optical and piezoelectric surface techniques

Reversible 2D/3D coatings from zipper-assembly of block copolymer micelles

A zipper-assembly of micelles into 2D/3D coatings is reported. Block copolymer micelles that incorporate a poly(n-octadecyl methacrylate) block are zipped and unzipped on demand onto a PMMA surface. The mechanism implies an interdigitation of molecular brushes enabling 15 nm micelles to be assembled into monolayers or multilayers.

Amino acid derivatized arylenediimides: a versatile modular approach for functional molecular materials

Nature's elegant molecular designs and their assemblies with specific structure-property correlations have inspired researchers to design and develop bio-mimics for advanced functional applications. To realize such advanced molecular materials, naturally evolved amino acids are arguably the ideal auxiliaries due to their remarkable molecular/chiral recognition and distinctive sequence specific self-assembling properties. Over the years, this modular approach of derivatizing naphthalenediimides (NDIs) and perylenediimides (PDIs) with amino acids and peptides have resulted in several hitherto unknown molecular assemblies with phenomenal impact on their performance. Derivatization with versatile arylenediimides is especially interesting due to their wide spread applications in fields ranging from biomedicine to electronics. Herein some of these seminal reports of this rapidly emerging field and the design principles embraced are discussed.

Structure of adsorbed polyelectrolyte monolayers investigated by combining optical reflectometry and piezoelectric techniques

Polyelectrolyte monolayers on solid substrates are studied with optical reflectivity and the quartz crystal microbalance (QCM). In particular, we investigate the adsorption of anionic poly(styrene sulfonate) (PSS) on amino-functionalized silica as well as cationic poly(allylamine hydrochloride) (PAH) and poly-L-lysine (PLL) on bare silica. By comparing the dry and wet masses measured on identical substrates with these two techniques, we obtain information on the layer thickness and water content of these layers. Monolayers typically feature an adsorbed dry mass of about 0.1-2 mg/m(2), a layer thickness of 0.5-2 nm, and a water content of 20-50%. One finds that the layer thickness increases with increasing concentrations of monovalent salts and polyelectrolytes.