The field of self-assembled monolayers (SAMs) has witnessed tremendous growth in synthetic sophistication and depth of characterization over the past 15 years.1 However, it is interesting to comment on the modest beginning and on important milestones. The field really began much earlier than is now recognized. In 1946 Zisman published the preparation of a monomolecular layer by adsorption (self-assembly) of a surfactant onto a clean metal surface.2 At that time, the potential of self-assembly was not recognized, and this publication initiated only a limited level of interest. Early work initiated in Kuhn’s laboratory at Gottingen, applying many years of experience in using chlorosilane derivative to hydrophobize glass, was followed by the more recent discovery, when Nuzzo and Allara showed that SAMs of alkanethiolates on gold can be prepared by adsorption of di-n-alkyl disulfides from dilute solutions.3 Getting away from the moisture-sensitive alkyl trichlorosilanes, as well as working with crystalline gold surfaces, were two important reasons for the success of these SAMs. Many self-assembly systems have since been investigated, but monolayers of alkanethiolates on gold are probably the most studied SAMs to date. The formation of monolayers by self-assembly of surfactant molecules at surfaces is one example of the general phenomena of self-assembly. In nature, self-assembly results in supermolecular hierarchical organizations of interlocking components that provides very complex systems.4 SAMs offer unique opportunities to increase fundamental understanding of self-organization, structure-property relationships, and interfacial phenomena. The ability to tailor both head and tail groups of the constituent molecules makes SAMs excellent systems for a more fundamental understanding of phenomena affected by competing intermolecular, molecular-substrates and molecule-solvent interactions like ordering and growth, wetting, adhesion, lubrication, and corrosion. That SAMs are well-defined and accessible makes them good model systems for studies of physical chemistry and statistical physics in two dimensions, and the crossover to three dimensions. SAMs provide the needed design flexibility, both at the individual molecular and at the material levels, and offer a vehicle for investigation of specific interactions at interfaces, and of the effect of increasing molecular complexity on the structure and stability of two-dimensional assemblies. These studies may eventually produce the design capabilities needed for assemblies of three-dimensional structures.5 However, this will require studies of more complex systems and the combination of what has been learned from SAMs with macromolecular science. The exponential growth in SAM research is a demonstration of the changes chemistry as a disciAbraham Ulman was born in Haifa, Israel, in 1946. He studied chemistry in the Bar-Ilan University in Ramat-Gan, Israel, and received his B.Sc. in 1969. He received his M.Sc. in phosphorus chemistry from Bar-Ilan University in 1971. After a brief period in industry, he moved to the Weizmann Institute in Rehovot, Israel, and received his Ph.D. in 1978 for work on heterosubstituted porphyrins. He then spent two years at Northwestern University in Evanston, IL, where his main interest was onedimensional organic conductors. In 1985 he joined the Corporate Research Laboratories of Eastman Kodak Company, in Rochester, NY, where his research interests were molecular design of materials for nonlinear optics and self-assembled monolayers. In 1994 he moved to Polytechnic University where he is the Alstadt-Lord-Mark Professor of Chemistry. His interests encompass self-assembled monolayers, surface engineering, polymers at interface, and surfaces phenomena. 1533 Chem. Rev. 1996, 96, 1533−1554

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Formation and Structure of Self-Assembled Monolayers.

Poly(aryleneethynylene)s: Syntheses, Properties, Structures, and Applications

Dendron-mediated self-assembly, disassembly, and self-organization of complex systems have been investigated. The most ideal building blocks would need to display shape persistence in solution and in the solid state, since only this feature provides access to the use of complementary methods of structural analysis. Most supramolecular dendrimers are chiral even when they are constructed from nonchiral building blocks and are equipped with mechanisms that amplify chirality. This poses additional challenges associated with the understanding of the structural origin of chirality in different supramolecular structures through combinations of structural analysis methods. While many supramolecular structures assembled from dendrimers and dendrons resemble some of the related morphologies generated from block-copolymers, they are much more complex and are not determined by the volume ratio between the dissimilar parts of the molecule.

Dendron-Mediated Self-Assembly, Disassembly, and Self-Organization of Complex Systems

The discovery of electrically conducting organic crystals1 and polymers1,2,3,4 has widened the range of potential optoelectronic materials5,6,7,8,9, provided these exhibit sufficiently high charge carrier mobilities6,7,8,9,10 and are easy to make and process. Organic single crystals have high charge carrier mobilities but are usually impractical11, whereas polymers have good processability but low mobilities1,12. Liquid crystals exhibit mobilities approaching those of single crystals and are suitable for applications13,14,15,16,17,18, but demanding fabrication and processing methods limit their use. Here we show that the self-assembly of fluorinated tapered dendrons can drive the formation of supramolecular liquid crystals with promising optoelectronic properties from a wide range of organic materials. We find that attaching conducting organic donor or acceptor groups to the apex of the dendrons leads to supramolecular nanometre-scale columns that contain in their cores π-stacks of donors, acceptors or donor–acceptor complexes exhibiting high charge carrier mobilities. When we use functionalized dendrons and amorphous polymers carrying compatible side groups, these co-assemble so that the polymer is incorporated in the centre of the columns through donor–acceptor interactions and exhibits enhanced charge carrier mobilities. We anticipate that this simple and versatile strategy for producing conductive π-stacks of aromatic groups, surrounded by helical dendrons, will lead to a new class of supramolecular materials suitable for electronic and optoelectronic applications.

Self-organization of supramolecular helical dendrimers into complex electronic materials

The living cationic ring-opening polymerization of 2-oxazolines has been studied in great detail since its discovery in 1966. The versatility of this living polymerization method allows copolymerization of a variety of 2-oxazoline monomers to give a range of tunable polymer properties that enable, for example, hydrophilic, hydrophobic, fluorophilic, as well as hard and soft materials to be obtained. However, this class of polymers was almost forgotten in the 1980s and 1990s because of their long reaction times and limited application possibilities. In the new millennium, a revival of poly(2-oxazoline)s has arisen because of their potential use as biomaterials and thermoresponsive materials, as well as the easy access to defined amphiphilic structures for (hierarchical) self-assembly. Recent developments that illustrate the potential of poly(2-oxazoline)s are discussed in this Review. In addition, the promising combination of poly(2-oxazoline)s and click chemistry is illustrated.

Poly(2‐oxazoline)s: A Polymer Class with Numerous Potential Applications

Preparation d'une serie de polymeres en peigne contenant le fragment carbazole donneur dans la chaine laterale, les poly [(N-alkylcarbazolyl-3) methyl methacrylates] avec alkyl n=1-16 et leurs complexes interpolymeriques EDA avec un polymere accepteur, le poly [(dinitro-3,5 benzoyl)-2 oxy ethyl methacrylate] sont etudies par DSC

Interchain electron donor-acceptor complexes: a model to study polymer-polymer miscibility?

Polycondensation a l'etat fondu de dialkoxy-2,5 hydroquinones avec l'acide terephtalique d'une part et le diacide-1,4 bicyclo [2.2.2] octane l'autre part. Fusion des polyesters bicycliques dans un liquide isotrope et de la plupart des terephtalates dans une phase cristalline. Structure stratifiee des 2 types de polyesters cristallises avec une distance intercouche augmentant avec la longueur de la chaine laterale. Preparation de polyterephtalate contenant 4 chaines laterales par motif et comparaison avec les proprietes des polyesters precedents

A comparative study of mesophase formation in rigid chain polyesters with flexible side chains

Preparation des polymeres cristaux liquides thermotropes contenant le mesogene methoxy-4 hydroxy-4' biphenyle dans la chaine laterale et differents espaceurs entre les mesogenes et le squelette et caracterisation par DSC et microscopie optique

Poly(vinyl ether)s and poly(propenyl ether)s containing mesogenic groups: a new class of side-chain liquid-crystalline polymers

https://csegroups.case.edu/vuv/files/1105solmat-optprop-cpvmatls.pdf

Optical properties of polymeric materials for concentrator photovoltaic systems

A partially-fluorinated surfactant having internal methylene groups and having the formula Rf --(CH2)m --R'f --COOM wherein m is 1-3, Rf is perfluoroalkyl or perfluoroalkoxy, containing 3-8 carbon atoms, R'f is linear or branched perfluoroalkylene containing 1-4 carbon atoms, and M is NH4, Li, Na, K, or H is useful in polymerization of fluorinated monomers. High molecular weight can be achieved in homopolymerization of tetrafluoroethylene.

Jose Manuel Rodriguez-Parada

Papers

Interchain electron donor-acceptor complexes: a model to study polymer-polymer miscibility?

A comparative study of mesophase formation in rigid chain polyesters with flexible side chains

Poly(vinyl ether)s and poly(propenyl ether)s containing mesogenic groups: a new class of side-chain liquid-crystalline polymers

Optical properties of polymeric materials for concentrator photovoltaic systems

Hydrogen-containing flourosurfacant and its use in polymerization