Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

https://science.sciencemag.org/content/sci/254/5036/1312.full.pdf

Molecular self-assembly and nanochemistry: a chemical strategy for the synthesis of nanostructures.

Low Molecular Mass Gelators of Organic Liquids and the Properties of Their Gels

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

Microemulsion-based media as novel drug delivery systems

Though the structures presented in crystallographic models of macromolecules appear to possess rock-like solidity, real proteins and nucleic acids are not particularly rigid. Most structural work to date has centred upon the native state of macromolecules, the most probable macromolecular form. But the native state of a molecule is merely its most abundant form, certainly not its only form. Thermodynamics requires that all other possible structural forms, however improbable, must also exist, albeit with representation corresponding to the factor exp( — Gi/RT) for each state of free energy Gi (see Moelwyn-Hughes, 1961), and one appreciates that each molecule within a population of molecules will in time explore the vast ensemble of possible structural states.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033583500005217

Hydrogen exchange and structural dynamics of proteins and nucleic acids

Artifact-free electron micrographs and rheological properties of aqueous solutions of cetyltrimethylammonium chloride (CTAC) with salicylate (from NaSal) as the binding counterion, are presented as a function of counterion concentration.

Viscoelastic micellar solutions: microscopy and rheology

Direct imaging of surfactant micelles, vesicles, discs, and ripple phase structures by cryo-transmission electron microscopy

Superspreading of water—silicone surfactant on hydrophobic surfaces

The prediction that molecular asymmetry alone is sufficient to force a phase transition from a disordered to an ordered phase in a system of rodlike particles has been investigated using α-helical synthetic polypeptides as the source of rodlike particles. To this end the temperature–composition phase diagrams for the two component systems polybenzylglutamate (PBLG)–dimethylformamide (DMF) and polycarbobenzoxylysine (PCBL)–dimethylformamide are compared with the Flory lattice model for rigid impenetrable rods. The experimental systems exhibit and the theory predicts three distinct regions in the phase diagram: a narrow biphasic region in which isotropic and liquid crystal phases differing only slightly in composition coexist, a transition region over which solvent is increasingly excluded from the coexisting ordered phase and rods excluded from the coexisting isotropic phase, and a region where almost pure solvent coexists with a highly concentrated liquid crystal phase. A detailed comparison of the theoretical phase diagram for rigid, impenetrable rods with the experimental ones reveals discrepancies which can be attributed to the facts that the experimental rods are neither completely rigid nor impenetrable. Analysis of thermal data on PBLG–DMF indicates that the latent heat for the isotropic to liquid crystal phase transition is small and endothermic. We conclude that molecular asymmetry alone is sufficient to produce a phase transition to an ordered phase. Dynamical data show that the bulk viscosity may be considerably lower in the ordered than in the disordered phase. Although rod motion in the liquid crystal phase is correlated, electron spin resonance data suggest that individual rod motion about its mean lattice position is greater than in the isotropic solution of equivalent concentration. Additional electron spin resonance studies show that the motion of small rods and of the polymer side-chains is little affected by the presence of a high concentration of long rods, whereas the tumbling of long rods is dramatically influenced by the presence of other long rods.

Wilmer G. Miller

Papers

Viscoelastic micellar solutions: microscopy and rheology

Direct imaging of surfactant micelles, vesicles, discs, and ripple phase structures by cryo-transmission electron microscopy

Superspreading of water—silicone surfactant on hydrophobic surfaces

Thermodynamics and dynamics of polypeptide liquid crystals

Liquid crystal-isotropic phase equilibriums in the system poly(.gamma.-benzyl .alpha.-L-glutamate)-methylformamide