Self-assembled Molecular Aggregates Research Articles

Interplay of Active Stress and Driven Flow in Self-Assembled, Tumbling Active Nematics

Lyotropic chromonic liquid crystals (LCLCs) are a special type of hierarchical material in which self-assembled molecular aggregates are responsible for the formation of liquid crystal phases. Thanks to its unusual material properties and bio compatibility, it has found wide applications including the formation of active nematic liquid crystals. Recent experiments have uncovered tumbling character of certain LCLCs. However, how tumbling behavior modifies structure and flow in driven and active nematics is poorly understood. Here, we rely on continuum simulation to study the interplay of extensile active stress and externally driven flow in a flow-tumbling nematic with a low twist modulus to mimic nematic LCLCs. We find that a spontaneous transverse flow can be developed in a flow-tumbling active nematic confined to a hybrid alignment cell when it is in log-rolling mode at sufficiently high activities. The orientation of the total spontaneous flow is tunable by tuning the active stress. We further show that activity can suppress pressure-driven flow of a flow-tumbling nematic in a planar-anchoring cell but can also promote a transition of the director field under a pressure gradient in a homeotropic-anchoring cell. Remarkably, we demonstrate that the frequency of unsteady director dynamics in a tumbling nematic under Couette flow is invariant against active stress when below a threshold activity but exhibits a discontinuous increase when above the threshold at which a complex, periodic spatiotemporal director pattern emerges. Taken together, our simulations reveal qualitative differences between flow-tumbling and flow-aligning active nematics and suggest potential applications of tumbling nematics in microfluidics.

Engineering couplings for exciton transport using synthetic DNA scaffolds

Summary Control over excitons enables electronic energy to be harnessed and transported for light harvesting and molecular electronics. Such control requires nanoscale precision over the molecular components. Natural light-harvesting systems achieve this precision through sophisticated protein machinery, which is challenging to replicate synthetically. Here, we introduce a DNA-based platform that spatially organizes cyanine chromophores to construct tunable excitonic systems. We synthesized DNA-chromophore nanostructures and characterized them with ensemble ultrafast and single-molecule spectroscopy and structure-based modeling. This synthetic approach facilitated independent control over the coupling among the chromophores and between the chromophores and the environment. We demonstrated that the coupling between the chromophores and the environment could enhance exciton transport efficiency, highlighting the key role of the environment in driving exciton dynamics. Control over excitons, as reported here, offers a path toward the development of designer nanophotonic devices.

Unraveling intra-aggregate structural disorder using single-molecule spectroscopy.

Structural disorder within self-assembled molecular aggregates may have strong effects on their optical functionality. Such disorder, however, is hard to explore using standard ensemble measurements. In this paper, we report on the characterization of intra-aggregate structural disorder through a linewidth analysis of fluorescence excitation experiments on individual zinc-chlorin (ZnChl) nanotubular molecular aggregates. Recent experiments suggest an anomaly in the linewidths of the two absorption bands that dominate the spectra: the higher-energy bands on average show a smaller linewidth than the lower-energy bands. This anomaly is explored in this paper by analyzing and modeling the correlation of the two linewidths for each aggregate. We exploit a Frenkel exciton model to show that the experimentally observed correlation of linewidths and other statistical properties of the single-aggregate spectra can be explained from small variations of the molecular orientations within individual aggregates.

Photochemical dynamics under incoherent illumination: Light harvesting in self-assembled molecular J-aggregates.

Transport phenomena in organic, self-assembled molecular J-aggregates have long attracted a great deal of attention due to their potential role in designing novel organic photovoltaic devices. A large number of theoretical and experimental studies have been carried out describing excitonic energy transfer in J-aggregates under the assumption that excitons are induced by a coherent laser-light source or initialized by a localized excitation on a particular chromophore. However, these assumptions may not provide an accurate description to assess the efficiency of J-aggregates, particularly as building blocks of organic solar cells. Under natural conditions, J-aggregates would be subjected to an incoherent source of light (as is sunlight), which would illuminate the whole photosynthetic complex rather than a single molecule. In this work, we present the first study of the efficiency of photosynthetic energy transport in self-assembled molecular aggregates under incoherent sunlight illumination. By making use of a minimalistic model of a cyanine dye J-aggregate, we demonstrate that long-range transport efficiency is enhanced when exciting the aggregate with incoherent light. Our results thus support the conclusion that J-aggregates are, indeed, excellent candidates for devices where efficient long-range incoherently induced exciton transport is desired, such as in highly efficient organic solar cells.

Generalized Kasha’s Model: T-Dependent Spectroscopy Reveals Short-Range Structures of 2D Excitonic Systems

Summary Excitonic organic materials owe their tunable optoelectronic properties to intricate microscopic configurations, challenging for conventional characterization methods to resolve. We generalize Kasha’s model by incorporating the temperature (T)-dependent absorption peak shift, in addition to the monomer-aggregate absorption peak shift that defines J- and H-aggregates, to characterize the microscopic structures. We show that the short-range interactions dominate in determining the direction of the T-dependent peak shift, which accounts for previously observed T-dependent blueshifting J-aggregates (BJ-aggregates) that were not explained and predicts the existence of redshifting H-aggregates (RH-aggregates). This defines four types of excitonic aggregates: RJ-, BH-, BJ-, and RH-aggregates, where the latter two unconventional aggregates are possible because of the two dimensionality of excitonic systems and cannot be understood with the original Kasha’s theory. Our conceptual framework is useful for elucidating structure-function relationships in molecular excitonic systems and is fully compatible with existing tools. Possible extensions to other spectroscopic observables and related systems are discussed.

Tuning effect of local environment to control mechanism of fluorescence depolarization: Rotational diffusion and resonance energy transfer within homo-aggregates of xanthenes

Controlling excitation energy transfer within self-assembled molecular aggregates has been a major challenge since such systems represent as prototypes for highly efficient light-harvesting pigment assemblies within photosynthetic organisms. Using time-resolved fluorescence depolarization studies, here we report complete reversal of trends in anisotropy decay traces up on increasing fluorophore concentration while traversing a series of solvent mixtures (water and glycerol) with increasing viscosity. For glycerol, in dilute solution depolarization results from rotational diffusion whereas Förster resonance energy transfer (FRET) is found to be the key mechanism in concentrated solution; in contrast, for water, rotational diffusion is the dominant reason for fluorescence depolarization at all concentrations. We further investigate how viscosity, rather than dielectric constant of the solvent, controls contribution from FRET towards depolarization by partially immobilizing the fluorophores. The results are explained within the framework of analytical models for fluorescence depolarization due to either rotational diffusion or FRET. We further examine the unusual ‘dip-and-rise’ behavior in anisotropy traces for intermediate range of concentration which is suggestive of presence of heterogeneity within homochromophoric system. These results show how one can fine-tune the explicit nature of solvent to facilitate FRET over other competing dynamical processes.

Direct Imaging of Exciton Transport in Tubular Porphyrin Aggregates by Ultrafast Microscopy.

Long-range exciton transport is a key challenge in achieving efficient solar energy harvesting in both organic solar cells and photosynthetic systems. Self-assembled molecular aggregates provide the potential for attaining long-range exciton transport through strong intermolecular coupling. However, there currently lacks an experimental tool to directly characterize exciton transport in space and in time to elucidate mechanisms. Here we report a direct visualization of exciton diffusion in tubular molecular aggregates by transient absorption microscopy with ∼200 fs time resolution and ∼50 nm spatial precision. These direct measurements provide exciton diffusion constants of 3-6 cm2 s-1 for the tubular molecular aggregates, which are 3-5 times higher than a theoretical lower bound obtained by assuming incoherent hopping. These results suggest that coherent effects play a role, despite the fact that exciton states near the band bottom crucial for transport are only weakly delocalized (over <10 molecules). The methods presented here establish a direct approach for unraveling the mechanisms and main parameters underlying exciton transport in large molecular assemblies.

Morphogenesis of defects and tactoids during isotropic–nematic phase transition in self-assembled lyotropic chromonic liquid crystals

We explore the structure of nuclei and topological defects in the first-order phase transition between the nematic (N) and isotropic (I) phases in lyotropic chromonic liquid crystals (LCLCs). The LCLCs are formed by self-assembled molecular aggregates of various lengths and show a broad biphasic region. The defects emerge as a result of two mechanisms: (1) surface-anisotropy that endows each N nucleus (‘tactoid’) with topological defects thanks to preferential (tangential) orientation of the director at the closed I–N interface, and (2) Kibble mechanism with defects forming when differently oriented N tactoids merge with each other. Different scenarios of phase transition involve positive (N-in-I) and negative (I-in-N) tactoids with nontrivial topology of the director field and also multiply connected tactoid-in-tactoid configurations. The closed I–N interface limiting a tactoid shows a certain number of cusps; the lips of the interface on the opposite sides of the cusp make an angle different from π. The N side of each cusp contains a point defect-boojum. The number of cusps shows how many times the director becomes perpendicular to the I–N interface when one circumnavigates the closed boundary of the tactoid. We derive conservation laws that connect the number of cusps c to the topological strength m of defects in the N part of the simply connected and multiply connected tactoids. We demonstrate how the elastic anisotropy of the N phase results in non-circular shape of the disclination cores. A generalized Wulff construction is used to derive the shape of I and N tactoids as a function of I–N interfacial tension anisotropy in the approximation of frozen director field of various topological charges m. The complex shapes and structures of tactoids and topological defects demonstrate an important role of surface anisotropy in morphogenesis of phase transitions in liquid crystals.

Aligned Layers of Silver Nano-Fibers.

We describe a new dichroic polarizers made by ordering silver nano-fibers to aligned layers. The aligned layers consist of nano-fibers and self-assembled molecular aggregates of lyotropic liquid crystals. Unidirectional alignment of the layers is achieved by means of mechanical shearing. Aligned layers of silver nano-fibers are partially transparent to a linearly polarized electromagnetic radiation. The unidirectional alignment and density of the silver nano-fibers determine degree of polarization of transmitted light. The aligned layers of silver nano-fibers might be used in optics, microwave applications, and organic electronics.

Chiral symmetry breaking by spatial confinement in tactoidal droplets of lyotropic chromonic liquid crystals

In many colloidal systems, an orientationally ordered nematic (N) phase emerges from the isotropic (I) melt in the form of spindle-like birefringent tactoids. In cases studied so far, the tactoids always reveal a mirror-symmetric nonchiral structure, sometimes even when the building units are chiral. We report on chiral symmetry breaking in the nematic tactoids formed in molecularly nonchiral polymer-crowded aqueous solutions of low-molecular weight disodium cromoglycate. The parity is broken by twisted packing of self-assembled molecular aggregates within the tactoids as manifested by the observed optical activity. Fluorescent confocal microscopy reveals that the chiral N tactoids are located at the boundaries of cells. We explain the chirality induction as a replacement of energetically costly splay packing of the aggregates within the curved bipolar tactoidal shape with twisted packing. The effect represents a simple pathway of macroscopic chirality induction in an organic system with no molecular chirality, as the only requirements are orientational order and curved shape of confinement.

Ultrafast Dynamics of Frenkel Excitons in Tetracene and Rubrene Single Crystals

Characteristics of thermally driven environmental motion (i.e., spectral densities) similarly control energy and charge-transport processes in self-assembled molecular aggregates, crystalline molecular solids, and photosynthetic antennae. A true microscopic understanding of these transport processes necessarily involves decomposing the spectral density of thermal noise into contributions from specific nuclear motions (i.e., modes). To this end, molecular solids may serve as excellent model systems due to their known crystal structures and well-defined intermolecular modes. Here, the electronic relaxation dynamics of tetracene (Tc) and rubrene (Rb) single crystals are investigated using a variety of nonlinear optical spectroscopies in conjunction with a Frenkel exciton model. Parameterization of the model is achieved by comparing simulated optical signals with those measured in experiments. In addition, electronic population transfer rates are computed with this same set of parameters using a modified Redfield theory. An important aspect of the model is its use of femtosecond stimulated Raman spectroscopies to obtain nuclear mode-specific spectral densities (i.e., polarizability spectral densities). Attainment of the spectral densities facilitates the interpretation of electronic spectroscopies, which are sensitive to both exciton delocalization and population transfer kinetics. One important prediction of the model, which is based on the comparison of low-temperature linear absorption spectra and model calculations, is that the exciton sizes for both Tc and Rb are approximately 18 molecules at 200 and 78 K, respectively. In addition, transient grating experiments detect sub-100 fs intraband population transfer processes in both crystals. Photon echo experiments and model calculations further support the assignment of these dynamics to electronic population transfer. The role of spatial correlations in the spectral densities at different molecular sites is also investigated. Calculations predict a remarkable behavior in which variation in the amount of spatial correlation for just a single mode in the spectral density, among many, causes the electronic relaxation rates to vary over an order of magnitude. This finding holds for both crystals and will likely generalize to molecular aggregates and photosynthetic antennae, thereby contributing to a microscopic understanding of phenomena that originate in spatially correlated fluctuations (e.g., coherent energy transfer).

Preparation and applications of a variety of fluoroalkyl end-capped oligomer/hydroxyapatite composites

A variety of fluoroalkyl end-capped oligomers were applied to the preparation of fluorinated oligomer/hydroxyapatite (HAp) composites (particle size: 38–356 nm), which exhibit a good dispersibility in water and traditional organic solvents. These fluoroalkyl end-capped oligomer/HAp composites were easily prepared by the reactions of disodium hydrogen phosphate and calcium chloride in the presence of self-assembled molecular aggregates formed by fluoroalkyl end-capped oligomers in aqueous solutions. In these fluorinated HAp composites thus obtained, fluoroalkyl end-capped acrylic acid oligomers and 2-methacryloyloxyethanesulfonic acid oligomer/HAp nanocomposites afforded transparent colorless solutions toward water; however, fluoroalkyl end-capped N , N -dimethylacrylamide oligomer and acryloylmorpholine oligomer were found to afford transparent colorless solutions with trace amounts of white-colored HAp precipitants under similar conditions. HAp could be encapsulated more effectively into fluorinated 2-methacryloyloxyethanesulfonic acid oligomeric aggregate cores to afford colloidal stable fluorinated oligomer/HAp composites, compared to that of fluorinated acrylic acid oligomers. These fluorinated oligomer/HAp composites were applied to the surface modification of glass and PVA to exhibit a good oleophobicity imparted by fluorine. HAp formation was newly observed on the modified polyethylene terephthalate film surface treated with fluorinated 2-methacryloyloxyethanesulfonic acid oligomers and acrylic acid oligomer/HAp composites by soaking these films into the simulated body fluid.

Development of Fluorinated Polymeric Functional Materials Using Fluorinated Organic Peroxide as Key Material

Fluoroalkanoyl peroxide [RF-C(=O)OO(O=)C-RF] decomposes homolytically through concerted three bond radical fission to afford fluoroalkyl radical (RF·) selectively, although the corresponding alkanoyl peroxide [R-C(=O)OO(O=)C-R] decomposes homolytically through stepwise radical fission to afford acyloxy radical [R-C(=O)O·] and alkyl radical [R·]. This decomposition of fluoroalkanoyl peroxide was applied to the direct fluoroalkylation of two end-sites of vinylsilane oligomers and (meth)acrylate oligomers. Fluoroalkyl end-capped trimethoxyvinylsilane oligomers [RF-(CH2CHSi(OMe)3)n-RF] thus obtained were applied to the surface modification on glass and traditional organic polymers such as PMMA and rubbers to exhibit not only strong hydrohobicity but good oleophobicity imparted by fluorine with extremely higher adhesive property on their surface. Fluoroalkyl end-capped actylate and methacrylate oligomers exhibited surface active properties imparted by fluorine, the same as for low-molecular weight fluorinated surfactants, and these fluorinated cooligomers formed the nanometer size-controlled self-assembled molecular aggregates in aqueous and organic media. These fluorinated molecular aggregates interacted with a variety of guest molecules such as low molecular biocides, fullerenes, and carbon nanotubes to afford the corresponding fluorinated oligomers/guest molecules nanocomposites. These fluorinated oligomers were applied to the preparation of fluorinated oligomers/silica gel nanocomposites and cross-linked fluorinated oligomeric nanoparticles.

Electrical and optical studies of gap states in self-assembled molecular aggregates

We fabricated a variety of two-terminal devices using self-assembled monolayers (SAM) of solid-state mixtures comprised of molecular “wires” [1,4-methane-benzenedithiol (Me-BDT)] and molecular insulator “spacers” [1-pentanethiol], which were prepared at various molar concentrations ratio, r of wires/spacers, and sandwiched between two gold electrodes. The devices’ electrical transport was investigated at several r values using the bias voltage (V) dependencies of the conductance and differential conductance at various temperatures. In parallel, we also studied the UV-visible absorption and photoluminescence (PL) emission spectra of the SAM mixtures grown on silica transparent substrates. For r&amp;gt;10−3 we found that two-dimensional (2D) Me-BDT aggregates are formed in the SAM films leading to novel properties compared to SAM films of isolated Me-BDT molecules at concentrations 10−8&amp;lt; r&amp;lt;10−4, which we studied before [V. Burtman, A. S. Ndobe, and Z. V. Vardeny, J. Appl. Phys. 98, 034314 (2005)]. First, an Ohmic response in the current-voltage (I-V) characteristics is obtained up to V∼0.5 V, which results in a new band in the differential conductance spectrum around V=0. Second, a new subgap absorption band is formed at ∼2.4 eV, which is related to a new yellow/red PL emission band. The novel optical and electrical properties of the 2D Me-BDT aggregates are explained by the formation of an electronic continuum band in the Me-BDT energy gap, which is caused by weak in-plane charge delocalization among the molecules forming the aggregates. To verify this model we also studied SAM molecular aggregate diodes using Al electrodes. The 1-eV difference in the electrode work function between Au and Al metals results in a pronounced EF shift with respect to the aggregate-related continuum band in the gap, and consequently, dramatically changes the device I-V characteristics.

Preparation and applications of novel fluoroalkyl end-capped oligomers/calcium carbonate nanocomposites

Calcium chloride reacted with sodium carbonate in the presence of a variety of self-assembled molecular aggregates formed by fluoroalkyl end-capped acrylic acid, 2-methacryloyloxyethane sulfonic acid, dimethylacrylamide, and acryloylmorpholine oligomers in aqueous solutions to afford the corresponding fluorinated oligomers/calcium carbonate composites in excellent to moderate isolated yields. These fluorinated calcium carbonate composites thus obtained were shown to have a good dispersibility not only in water but also in traditional organic media including fluorinated solvents. Dynamic light scattering measurements (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that these fluorinated composites are nanometer-size-controlled particles and well dispersed in these media. Cross-linked fluoroalkyl end-capped acrylic acid co-oligomer containing poly(oxyethylene) units was also applied to the preparation of new cross-linked fluorinated calcium carbonate nanocomposites under similar conditions. The obtained cross-linked fluorinated calcium carbonate nanocomposites were found to have an extremely higher dispersibility in aqueous and organic media including fluorinated solvents, compared to that of the corresponding fluoroalkyl end-capped oligomer nanocomposites. In particular, it was verified that these fluorinated calcium carbonate nanocomposites are applicable to the dispersion above poly(methyl methacrylate) (PMMA) film surface. Interestingly, field-emission SEM (FE-SEM) images of the cross-section of the modified PMMA films showed that calcium carbonate particles dispersed into these PMMA films could be arranged regularly above the modified film surface. More interestingly, cross-linked fluorinated oligomeric aggregates were able to provide suitable host moieties for the crystallization of calcium carbonate.

SYNTHESIS AND APPLICATIONS OF NOVEL FLUOROALKYL END-CAPPED OLIGOMERS CONTAINING 3,5-DIMETHYL-4-HYDROXYBENZYL AND 3-(2H-BENZOTRIAZOL-2-yl)-4-HYDROXYPHENYL SEGMENTS

New fluoroalkyl end-capped co-oligomers containing 3,5-dimethyl-4-hydroxybenzyl segments [RF‒(DMHB)x‒(DMAA)y–RF] were prepared by the reactions of fluoroalkanoyl peroxides with N-(3,5-dimethyl-4-hydroxybenzyl)methacrylamide [DMHB] and N,N-dimethylacrylamide (DMAA). Similarly, fluoroalkyl end-capped homo- and co-oligomers containing 3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl segments [RF–(BTRI)x–(Co–M)y–RF] were prepared by the reactions of fluoroalkanoyl peroxides with 2-[3–(2H‒benzotriazol–2–yl)–4–hydroxyphenyl]ethyl methacrylate [BTRI] and co-monomers [Co–M] such as acrylic acid (ACA), DMAA, and acryloylmorpholine (ACMO). The fluoroalkyl end-capped DMHB and BTRI co-oligomers thus obtained were soluble not only in water but also in common organic solvents. In addition, these fluorinated co-oligomers were able to reduce the surface tension of 0.1 N NaOH solutions quite effectively to around 20 mN/mlevels, although the corresponding non-fluorinated co-oligomers were not effective in reducing the surface tension of 0.1 N NaOH solutions. A modified polystyrene film surface treated with these fluoroalkyl end-capped DMHB and BTRI co-oligomers was found to exhibit a good oleophobicity imparted by fluorine with an excellent hydrophilicity. XPS analyses showed that end-capped fluoroalkyl groups in RF-(BTRI)n-RF homo-oligomer were arranged regularly above the modified polystyrene surface. Of particular interest, it was demonstrated that the self-assembled molecular aggregates formed by RF-(DMHB)x-(DMAA)y-RF co-oligomers could interact strongly with 7,7,8,8-tetracyanoquinodimethane (TCNQ) as a guest molecule to form a host–guest intermolecular complex, though such a host–guest interaction was not observed in the corresponding non-fluorinated DMHB co-oligomer.

Dispersion of gold nanoparticles above the poly(methyl methacrylate) surface by the use of fluoroalkyl end-capped oligomeric aggregates

Nanometer size-controlled gold particles were prepared under mild conditions by reducing the corresponding metal precursor in the presence of self-assembled molecular aggregates formed by fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers. The stable gold nanoparticles protected by these fluorinated molecular aggregates were applied to the dispersion above the poly(methyl methacrylate) film surface.

Synthesis of Amphiphilic Fluoroalkoxyl End-Capped Cooligomers Containing Oxime-Blocked Isocyanato Segments: Architecture and Applications of New Self-Assembled Fluorinated Molecular Aggregates

New fluoroalkoxyl end-capped cooligomers containing oxime-blocked isocyanato segments were prepared by the reactions of fluoroalkanoyl peroxides with isocyanatoethyl methacrylate 2-butanone oxime adduct (IEM-BO) and N,N-dimethylacrylamide (DMAA). Fluoroalkoxyl end-capped IEM-BO−DMAA cooligomers thus obtained were easily soluble in water and common organic solvents except for hexane. These amphiphilic fluoroalkoxyl end-capped cooligomers were able to reduce the surface tension of water quite effectively around to 18 mN/m levels with a clear break point resembling a cmc (critical micelle concentration). Static and dynamic light scattering measurements showed that fluoroalkoxyl end-capped IEM-BO−DMAA cooligomers are likely to form the self-assembled molecular aggregates in aqueous solutions. In particular, the longest fluoroalkoxyl end-capped IEM-BO−DMAA cooligomer can form the self-assemblies, which are considered to consist of around 100 fluorinated oligomeric molecules with 17−18 nm size even in the lower concentrations of the cooligomer, compared to the other fluoroalkoxylated cooligomers. The molecular assemblies formed by the longest fluoroalkoxyl end-capped IEM-BO−DMAA cooligomer could interact strongly with ethidium bromide (Etd-Br) as a guest molecule to form the host−guest intermolecular complex. Additionally, fluoroalkoxyl end-capped IEM-BO−DMAA cooligomers were found to become useful precooligomers for the introduction of various aromatic segments into the cooligomer chains. In fact, amphiphilic fluoroalkoxyl end-capped cooligomer-bound functional aromatic moieties such as 5-fluorouracil(5-FU) and 9-aminoacridine were prepared in good yields by the reactions of the corresponding fluorinated precooligomers with the parent aromatic compounds. In particular interest, it was demonstrated that fluoroalkoxyl end-capped cooligomer-bound 5-FU could have a remarkably strong interaction with oligoDNA.

Solubilization of cytochrome c in organic media with fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer: a new approach to fluorinated biocatalyst in organic media

Self-assembled molecular aggregates of fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer can solubilize cytochrome c in organic media such as methanol, although the corresponding non-fluorinated polymer cannot solubilize cytochrome c in organic media. Interestingly, the resulting fluorinated oligomer–cytochrome c aggregate was found to act effectively as a new fluorinated biocatalyst for the oxidation of pinacyanol chloride with hydrogen peroxide in the non-aqueous methanol.

Luminol chemiluminescence selectively stimulated with self-assembled molecular aggregates of fluoroalkylated end-capped N-(1,1-dimethyl-3-oxobutyl) acrylamide oligomer

Fluoroalkylated end-capped N-(1,1-dimethyl-3-oxobutyl) acrylamide oligomer is a unique host molecule accommodating luminol and potentially enhancing light emission yield in its chemiluminescence with hydrogen peroxide-potassium ferricyanide in an aqueous solution.