Water Subphase Research Articles

Towards sensory Langmuir monolayers consisting of macrocyclic pentaaminoanthraquinone

A pentaazamacrocycle incorporating an intracyclic anthraquinone fragment (PENTAQ) was synthesized with the aim of forming metal-responsive Langmuir monolayers. PENTAQ allows a good discrimination by naked eye of copper ions in methanol–water solutions (50 : 50 v/v). Spectrophotometric investigations of the protonation and Cu2+ binding properties of PENTAQ were undertaken in order to gain a deeper insight into the pH-dependent speciation as well as the color changing process. PENTAQ monolayers at air/water and air/methanol–water interfaces were prepared according to the Langmuir procedure. The structure of the monolayers can be tuned by varying the pH of the aqueous subphase, since it was found that the relative orientation at the interface of the aromatic lipophilic and polyazaalkyl hydrophilic fragments is critically dependent upon the protonation state of the immersed pentaazamacrocyclic chain. In situ fiber-optic UV-vis measurements revealed the formation of H-aggregates in the PENTAQ monolayer deposited on a water subphase at pH = 5.5. The ability of these films to detect copper(II) in the aqueous or methanol–water (20 : 80 v/v, pH = 9.8) subphase was explored by combining several experimental techniques, including pressure–area measurements (π–A isotherms), in situ UV-vis absorption spectrophotometry, and XPS spectroscopy.

Evidence for Interaction with the Water Subphase As the Origin and Stabilization of Nano-Domain in Semi-Fluorinated Alkanes Monolayer at the Air/Water Interface

Evidence for Interaction with the Water Subphase As the Origin and Stabilization of Nano-Domain in Semi-Fluorinated Alkanes Monolayer at the Air/Water Interface

Structure and physicochemical properties of cation polymethine dyes in Langmuir-Blodgett films

The physicochemical properties of monomolecular layers of amphiphilic cation polymethine dyes (i.e., thia- and oxacarbocyanines) on the surface of a water subphase are studied along with the conditions of Langmuir-Blodgett (LB) film preparation. The area occupied by one dye molecule in the liquid-stretched and liquid-condensed states of a monolayer is determined. Based on a comparison of experimental and theoretically calculated areas, the nature of dye packing in monolayers is studied by means of molecular mechanics using data from conformation analysis. The spectral and luminescent properties of cationic polymethine dyes in various media are investigated. Excimer fluorescence is observed in LB films. The excimers in LB films are found to arise not from monomers but from dye dimers. A possible mechanism of their formation is considered.

Amaranth 7S Globulin Langmuir Films and Its Interaction with l-α-Dipalmitoilphosphatidilcholine at the Air–Fluid Interface

Amaranth seeds are one of the more promising food ingredients, due to their high protein content, among which the most important are storage proteins known as globulins. However, little is known about the physicochemical of the globulin proteins. In this work, we study the physicochemical behavior of films made of amaranth 7S globulin and its interaction with a model membrane made of L-α-dipalmitoylphosphatidylcholine (L-α-DPPC) at the air-liquid interface. The study was done by means of Langmuir balance, Brewster angle microscopy (BAM), fluorescence microscopy, and atomic force microscopy (AFM). We found that isotherms of pure 7S globulin directly deposited on either water or buffer subphases behave similarly and globulin forms a condensed film made of globular and denature structures, which was confirmed by BAM observations. Good mixtures of the protein with L-α-DPPC are formed at low surface pressure. However, they phase separate from moderate to high surface pressure as observed by BAM. Isotherms detect the presence of the protein in the mixture with L-α-DPPC, but we were unable to detect it through BAM or AFM. We show that fluorescence microscopy is a very good technique to detect the presence of the protein when it is well-mixed within the LE phase of the lipid. AFM images clearly show the formation of protein mono- and multilayers, and in phase mode, we detected domains that are formed by protein and LE lipid phase, which were corroborated by fluorescence microscopy. We have shown that globulin 7S mix well with lipid phases, which could be important in food applications as stabilizers or emulsifiers, but we also show that they can phase separate with a moderate to high surface pressure.

Interfacial growth of large-area single-layer metal-organic framework nanosheets

The air/liquid interface is an excellent platform to assemble two-dimensional (2D) sheets of materials by enhancing spontaneous organizational features of the building components and encouraging large length scale in-plane growth. We have grown 2D molecularly-thin crystalline metal-organic-framework (MOF) nanosheets composed of porphyrin building units and metal-ion joints (NAFS-13) under operationally simple ambient conditions at the air/liquid interface. In-situ synchrotron X-ray diffraction studies of the formation process performed directly at the interface were employed to optimize the NAFS-13 growth protocol leading to the development of a post-injection method –post-injection of the metal connectors into the water subphase on whose surface the molecular building blocks are pre-oriented– which allowed us to achieve the formation of large-surface area morphologically-uniform preferentially-oriented single-layer nanosheets. The growth of such large-size high-quality sheets is of interest for the understanding of the fundamental physical/chemical properties associated with ultra-thin sheet-shaped materials and the realization of their use in applications.

The stability performances of epoxy resin-based monolayers on resisting disruption of temperature and wind

In this paper, epoxy resin-based monolayers (ER monolayers) were prepared as water evaporation retardants. The interfacial stability performances of molecular films on resisting disruption of temperature and wind were investigated. The dependence of evaporation resistance on temperature was explicit and supported. Energy barrier theory was performed to explain the retardation mechanism of water evaporation of ER monolayers. The disruption of wind on monolayers was researched through simulation of surface waves over the subphase water. The results showed that ER monolayers presented better stability to resist disturbances of temperature shift and surface waves compared to C16OH monolayer. ER monolayers had a good effect on retardation of water evaporation due to their ability to spread spontaneously and form closely packed films over the water surface.

Interfacial Self-Assembly and Characterization of Chiral Coordination Polymer Multilayers with Bidentate Ligands of Hydroquinine Anthraquinone-1,4-diyl Diether as Linkers

Chiral coordination polymers (CPs) have been prepared at the air-water interface by using the ligand of 1,4-bis(9-O-dihydroquininyl)anthraquinone [(DHQ)2AQN] and its enantiomer of 1,4-bis(9-O-dihydroquinidinyl)anthraquinone [(DHQD)2AQN] as linkers and AgNO3 as the connector. Surface pressure-area isotherms indicated that both ligands could form insoluble monomolecular layers on the pure water and AgNO3 subphase surfaces. Compared with the average molecular area on the pure water surface, that of the ligand increased about 10% when its monolayer was formed on the AgNO3 subphase surface due to the formation of Ag-(DHQ)2AQN and Ag-(DHQD)2AQN chiral CPs. These monolayers were deposited on the quartz, Si, and indium tin oxide (ITO) substrate surfaces via the Langmuir-Blodgett (LB) method. The as-prepared LB films were characterized by using UV-vis absorption and fluorescence spectroscopy, circular dichroism and X-ray photoelectron spectroscopy, as well as by using a scanning electron microscope and atomic force microscope. Broad fluorescence emissions were measured at about 365 and 525 nm for the ligands in the methanol solutions. The second emission red shifted to about 555 nm in the LB films of both pure ligands and their Ag-directed CPs. A couple of well-reversible redox waves were recorded and centered at about -0.2 ~ -0.3 V (vs Ag/AgCl) for the ITO electrode covered by the LB films of (DHQ)2AQN, (DHQD)2AQN, or of the Ag(+)-directed CPs, which were designated to one electron transfer process of the ligands. Small aggregates were observed for the LB films prepared at the lower surface pressures, which were compressed to form more uniform two-dimensional layers at the higher surface pressures.

Controlling the Structural and Electrical Properties of Diacid Oligo(Phenylene Ethynylene) Langmuir–Blodgett Films

The preparation, characterization and electrical properties of Langmuir-Blodgett (LB) films composed of a symmetrically substituted oligomeric phenylene ethynylene derivative, namely, 4,4'-[1,4-phenylenebis(ethyne-2,1-diyl)]dibenzoic acid (OPE2A), are described. Analysis of the surface pressure versus area per molecule isotherms and Brewster angle microscopy reveal that good-quality Langmuir (L) films can be formed both on pure water and a basic subphase. Monolayer L films were transferred onto solid substrates with a transfer ratio of unity to obtain LB films. Both L and LB films prepared on or from a pure water subphase show a red shift in the UV/Vis spectrum of about 14 nm, in contrast to L and LB films prepared from a basic subphase, which show a hypsochromic shift of 15 nm. This result, together with X-ray photoelectron spectroscopic and quartz crystal microbalance experiments, conclusively demonstrate formation of one-layer LB films in which OPE2A molecules are chemisorbed onto gold substrates and consequently -COO-Au junctions are formed. In LB films prepared on a basic subphase the other terminal acid group is also deprotonated and associates with an Na(+) counterion. In contrast, LB films prepared from a pure water subphase preserve the protonated acid group, and lateral H-bonds with neighbouring molecules give rise to a supramolecular structure. STM-based conductance studies revealed that films prepared from a basic subphase are more conductive than the analogous films prepared from pure water, and the electrical conductance of the deprotonated films also coincides more closely with single-molecule conductance measurements. This result was interpreted not only in terms of better electron transmission in -COO-Au molecular junctions, but also in terms of the presence of lateral H-bonds in the films formed from pure water, which lead to reduced conductance of the molecular junctions.

Effects of subphase composition on the monolayer behavior of “core–coronae” type hybrid amphiphiles

As described in this paper, the effect of solutes on monolayer properties of a “core–coronae” type amphiphile was studied. The “core–coronae” type hybrid amphiphile comprises double-decker-shaped polyhedral silsesquioxane (DDSQ) as a core and four di(ethylene glycol) (DEG) units as coronae (4DEG-DDSQ). The molecule was spread onto a water subphase containing phosphoric acid, 1,3-bis(hydroxymethyl)urea, or potassium chloride. Then monolayer properties were studied using surface pressure (π)–area (A) isotherm and Brewster angle microscope measurements. Addition of phosphoric acid and 1,3-bis(hydroxymethyl)urea to the water subphase increased the limiting surface area of the 4DEG-DDSQ monolayer compared to that prepared in the pure water surface. The surface area increase is attributed to formation of strong hydrogen bonding between OH groups of DEG units and solutes. Addition of KCl showed a negligible change in the π–A isotherm, even though DEG units coordinate with K+ ions. The monolayer spread on the different subphases was transferred onto a solid substrate and the morphology of the transferred film was observed using atomic force microscopy (AFM). The AFM images show a dot-like structure, irrespective of the subphase composition, whereas the dot size decreases and the dot density increases with addition of solutes.

Preparation, Characterization, and Photoelectric Properties of Langmuir–Blodgett Films of Some Europium-Substituted Polyoxometalates and 2-Aminofluorene with Tunable Emission Color

A new series of organic/inorganic composite Langmuir–Blodgett (LB) films consisting of 2-aminofluorene (Fl–NH2) as the π-conjugated organic molecule, an europium-substituted polyoxometalate (POM, POM = Na9EuW10O36, K13[Eu(SiW11O39)2] and K5[Eu(SiW11O39)(H2O)2], which are denoted by EuW10, EuW22 and EuW11, respectively) as the inorganic component, were prepared. Structural and photophysical characterization of these LB films were achieved by π–A isotherms, UV–Vis absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunneling microscopy, and surface photovoltage spectroscopy. Our experimental results indicate that stable Langmuir and LB films are formed in pure water and POM sub-phases. Luminescence spectra of the prepared hybrid LB films show that tunable emission color can be obtained due to the dual-emissive nature of the mixed Fl–NH2/POM blends. These 2-aminofluorene-based LB films displayed interesting electrical conductivity behavior. Among them, Fl–NH2/EuW11 3-layer films showed a good electrical response with the a tunneling current up to ± 100 nA when the voltage was monitored at −0.8 to 1.5 V. These LB composites show good photovoltage responses and a photovoltage of 2.7 μV can be obtained for the Fl–NH2/EuW22 system when it is excited by light.

Interfacial assembly and characterization of hybrid ultrathin films of manganese 5,10,15,20-tetra (4-pyridyl) porphine chloride tetrakis (methochloride) and its polymeric derivative with poly (4-vinylpyridine)

Monolayers of a water-soluble metalloporphyrin, manganese tetra-(4-pyridyl) porphine chloride tetrakis (methochloride) (MnTMPyP), and its polymeric derivative with poly (4-vinylpyridine) (MnTMPyP-PVP) have been investigated at the air–water interface. These monolayers were transferred on the substrate surfaces to form hybrid ultrathin films by the Langmuir-Blodgett (LB) method. It was revealed that, although the water-soluble MnTMPyP could not form insoluble monomolecular layer on the pure water surface, it could be stabilized on the NaB(C6H5)4 subphase surface due to an electrostatic interaction between MnTMPyP and B(C6H5)4−, resulting in the formation of MnTMPyP-B(C6H5)4 hybrids. On the other hand, its polymeric derivative of MnTMPyP-PVP could form stable insoluble monolayers on the pure water, NaB(C6H5)4 and Na2PdCl4 subphase surfaces. Composition, structure and microscopic morphology of the as-prepared LB films were characterized by using UV–vis absorption, infrared and X-ray photoelectron spectroscope, as well as scanning electron microscope. The results suggested formation of the hybrid MnTMPyP-B(C6H5)4 and MnTMPyP-(PVP-)B(C6H5)4 and Pd-MnTMPyP-PVP coordination polymer ultrathin films at the interfaces. Cyclic voltammograms of the LB films revealed two couples of reversible redox waves centered at 0.2–0.3 and −0.1 to −0.2V (vs Ag/AgCl), corresponding to the Mn(II)/Mn(III)TMPyP-(PVP-)B(C6H5)4 and Mn(III)/Mn(IV)TMPyP-(PVP-)B(C6H5)4 electron transfer processes of the manganese porphyrins in the LB films.

The influence of cardiolipin on phosphatidylglycerol/phosphatidylethanolamine monolayers—Studies on ternary films imitating bacterial membranes

In this work the properties of ternary systems composed of phosphatidylethanolamines (PEs), phosphatidylglycerols (PGs) and cardiolipin (CL) were studied with the Langmuir monolayer technique and Brewster Angle Microscopy. In all the investigated mixed films the PE:PG=3:1, which reflects the proportion of these lipids classes in various Gram Negative bacteria. The content of cardiolipin was varied from 5 to 20%, which is in the range of CL concentration in bacterial membranes. The experiments were performed for POPE/POPG/CL and POPE/DPPG/CL films spread on water subphase and on NaCl solution. It was found that the components of the studied films mix nonideally in the investigated range of the composition, however, the addition of cardiolipin weakens the interactions between the molecules. Thermodynamically unfavorable influence of CL results from the structure of this lipid, which due to sterical reasons disturbs the organization of POPE/PG film. It was also found that the presence of sodium ions in the subphase causes the increase of the area per molecule values and in general weakens the interactions between molecules in ternary films. However, the foregoing effect of NaCl both on binary PE/PG films as well as ternary PE/PG/CL monolayers was stronger on DPPG-containing films. The analysis of the collected data evidenced that the influence of cardiolipin as well as inorganic electrolyte on the properties of the studied films is directly connected with molecular structure of monolayers components.

Aggregation behavior of polystyrene-b-poly(acrylic acid) at the air–water interface

The aggregation behavior of amphiphilic block copolymer polystyrene-b-poly(acrylic acid) (PS-b-PAA) at the air–water interface was investigated through surface pressure measurements (isotherms, compression–expansion hysteresis and compression relaxation experiments), Brewster Angle Microscopy (BAM) imaging and Atomic Force Microscopy (AFM) imaging. It is found that PS-b-PAA (Mn = 11490 g mol−1, PAA wt%∼62%) forms a stable Langmuir monolayer on the water surface (pH = 7) by using N,N-dimethylformamide (DMF) as the spreading solvent. The aggregation of block copolymer is induced by an initial diffusion of DMF into water from the interface. Upon compression of the film, the pseudoplateau observed in the Langmuir isotherm corresponds to a “pancake-to-brush” transition with the PAA chains gradually dissolving in the water subphase and stretching underneath the PS cores. Based on the isotherms and the BAM images, it is suggested that the polymer chain dynamics in spreading solutions with different concentrations at the time of solvent diffusion influence the interfacial behavior of block copolymers significantly. The Langmuir–Blodgett (LB) films prepared at different surface pressures from different spreading solution concentrations were scanned by AFM. A variety of morphologies such as wormlike, porous and reticulate structures, and dots were observed. The isotherms and AFM images show the spreading solution concentration and surface pressure dependence of the aggregation behavior of PS-b-PAA copolymer at the air–water interface.

A coarse-grained model for polyethylene glycol in bulk water and at a water/air interface

A coarse-grained model for polyethylene glycol (PEG) in water has been developed using a combination of the iterative Boltzmann inversion (IBI) methodology and a suitable coarse-grained water potential. The combined coarse-grained model is shown to be effective in reproducing the properties of single chains in bulk water and multiple chains across a series of chain lengths and concentrations, and is transferable to PEG chains at a water/air interface. Good agreement is achieved with both experiment and reference atomistic simulations in an explicit solvent. Simulations of a single chain in aqueous solution yield a molecular weight (MW)-radius of gyration (Rg) relation that compares favourably with the reported scaling law from experiment. Simulations of multiple chains across a wide concentration range show no concentration dependence of Rg, in agreement with previous atomistic simulations. The model we develop is shown to be transferable between polymer in bulk water and at a water/air interface. For interfacial simulations, PEG chains are found to spontaneously migrate to the surface and adsorb to form a thin surface layer, which thickens with increasing surface concentration. The point at which the surface is fully saturated with polymer, and the polymer layer thicknesses obtained from simulations, are both in good agreement with experimental findings. At high surface concentrations, when the surface is fully saturated with polymer, ethylene oxide (EO) segments are found to extend into the water subphase as loop and tail conformations, with this extension increasing with further increases in the surface concentration. The coarse-grained model is noted to provide very large increases in simulation speed, with equilibration times of <1000× the reference atomistic models. We also consider a number of different coarse-grained models for water in this study, showing that the CSJ model adopted in this work [Chiu et al., J. Chem. Theory Comput., 2010, 6, 851] is far superior for studying water at a water/air surface, than many of the previous coarse-grained models of water.

Trimetallic Ag@AuPt Neapolitan nanoparticles

Trimetallic Ag@AuPt Neapolitan nanoparticles were prepared by two sequential galvanic exchange reactions of 1-hexanethiolate-capped silver nanoparticles (AgC6, 5.70 ± 0.82 nm in diameter) with gold(I)-thiomalic acid (Au(I)TMA) and platinum(II)-hexanethiolate (Pt(II)C6) complexes. The first reaction was carried out at the air-water interface by the Langmuir method where the AgC6 nanoparticles formed a compact monolayer and water-soluble Au(I)TMA was injected into the water subphase; the nanoparticles were then deposited onto a substrate surface in the up-stroke fashion and immersed into an acetone solution of Pt(II)C6. As both reactions were confined to an interface, the Au and Pt elements were situated on two opposite poles of the original Ag nanoparticles. The tripatchy structure was clearly manifested in elemental mapping of the nanoparticles, and consistent with the damping and red-shift of the nanoparticle surface plasmon resonance. Further characterizations by X-ray photoelectron spectroscopy showed that the reactions were mostly confined to the top layers of the Ag metal cores, and contact angle and infrared spectroscopic measurements confirmed the incorporation and segregated distribution of the organic capping ligands on the nanoparticle surface.

Pressure dependent surface morphology and Raman studies of semicrystalline poly(indole-5-carboxylic acid) by the Langmuir–Blodgett technique

Surface morphology and crystallinity play important roles in achieving high performance devices based on polymer thin films. The Langmuir–Blodgett (LB) method has been explored for the formation of uniform and ordered poly(indole-5-carboxylic acid) (5CPIn) films. The surface pressure vs. area isotherm of 5CPIn over a water subphase gives four distinct regions indicating a gaseous phase, a liquid condensed phase, a solid condensed phase and a region of collapsing solid and the formation of bilayers. The deposited monolayers of 5CPIn over indium tin oxide (ITO) substrates at different control pressures (in the selected regions of the pressure isotherm) are used to study the morphology and crystallinity. Our study reveals the region of pressure where one can obtain uniformity (at the nano level) and continuity of the films up to a few hundreds of a micron. Additionally, a comparative study using scanning electron microscopy, UV-vis spectroscopy and Raman spectroscopy indicates that the films obtained by the LB technique are significantly different to the films obtained by electropolymerization (EP) and drop casting (DC) techniques. The LB film of 5CPIn shows a more uniform morphology, a red shift of the highest absorption peak, and better crystallinity in comparison to the EP and DC polymer films. Additionally it also shows potential for polymer thin film devices.

The physical properties of lipid monolayers and bilayers containing calixarenes sensitive to cytochrome c

We studied physical properties of the monolayers and bilayer lipid membranes (BLM) formed by calix[6]arene carboxylic acid derivative (CX) and its mixtures with diphytanoylphosphatidylcholine (DPhPC) by means of measurement surface pressure, surface dipole potential and electrostriction. CX forms stable monolayers at an air-water interface and complexes in mixed monolayers contained DPhPC. Calixarenes increase the elastic moduli of lipid monolayers as well as BLM. Cytochrome c (cyt c) specifically binds to CX by incorporation of the amino groups of lysine residues at the protein surface. This binding affected the physical properties of CX monolayers depending on their initial surface pressure. Addition of cyt c into the water subphase induced increase of surface pressure of CX monolayers at relatively low initial pressure (15 mN/m) when monolayer was in liquid expanded state (LE). This may be due interaction of positively charged cyt c with negatively charged carboxylic groups of CX and also by its penetration into the air-water interface. However, much subtle changes were observed for higher initial surface pressure (20 and 35 mN/m) when monolayer is in liquid condensed (LC) and solid (S) state, respectively. Lysine induced substantially lower changes in surface pressure in comparison with that of cyt c.

The aggregation behavior of amphiphilic pyrene chromophore in solutions and langmuir monolayers

The aggregation behavior of 12-(1-pyrene)dodecanoic acid (PDDA) in chloroform and ethanol solutions and water-ethanol mixtures, as well as in monolayers at the air-water interface, has been investigated. It has been established that the bathochromic shift in electron absorption spectra (EAS) for the solutions observed during the transition from a more polar solvent (ethanol) to a less polar one (chloroform) is not related to the chromophore aggregation, but is caused by specific interactions of chloroform with the pyrene fragment of the amphiphilic molecule. These data were corroborated by the method of NMR spectroscopy (diffusion ordered spectroscopy (DOSY)), the results of which demonstrated that the diffusion coefficients and diffusing particles size in two organic solvents under study corresponded to the monomer form of PDDA. Inducing the excimer aggregation of the chromophore was carried out through an increase of the water content in the mixed water-ethanol solvent, in which, as was found, the solvating (shielding) ethanol capacity preventing pyrene aggregation with formation of excimers is preserved up to high concentrations of the “poor” solvent: the excimer emerges at a water content in the mixture exceeding 65%. The sequence of structural transformations in PDDA films on the water surface was suggested on the basis of the monolayers’ compression isotherms and absorption and fluorescence spectra. Using the PDDA monolayer, the polarity of the surface of the water subphase was estimated by juxtaposition of PA parameters of this 2D system and water-ethanol solutions of different polarities (component ratios) and it was demonstrated that the surface polarity corresponded to that of water-ethanol solutions containing sufficiently large amounts of the organic solvent (more than 20 vol % ethanol). The interaction of the PDDA monolayer with β-cyclodextrine (β-CD) added into the subphase has been examined.

Formation of Dynamic Duolayer Systems at the Air/Water Interface by using Non-ionic Hydrophilic Polymers

The inclusion of a water-soluble polymer, poly(vinyl pyrrolidone) (PVP), into a surface active film composition before application to the water surface leads to the formation of a dynamic duolayer; a novel surface film system. This duolayer shows improved surface viscosity over the monolayer compound alone, while the addition of polymer maintains other film properties such as evaporation control and equilibrium spreading pressure. Brewster Angle Microscopy shows that the duolayer film undergoes a different formation mechanism upon film compression, and the resultant surface pressure/area isotherm is different at lower surface pressures indicating the PVP is present on the water surface at these pressures and squeezed out to the water subphase at higher pressures. The addition of water-soluble polymers to form a dynamic duolayer provides a unique way to produce defect-free and tightly packed films while polymer is associated with the film. This finding provides new knowledge for the design of surface films with improved properties with potential applications in many areas.

Investigation of transmembrane protein fused in lipid bilayer membranes supported on porous silicon

This article investigates a device made from a porous silicon structure supporting a lipid bilayer membrane (LBM)fused with Epithelial Sodium Channel protein. The electrochemically-fabricated porous silicon template had pore diameters in the range 0.2~2 µm. Membranes were composed of two synthetic phospholipids: 1,2-diphytanoyl-sn-glycero-3-phosphoserine and 1,2-diphytanoyl-sn-glycero-3-phosphoethanolamine. The LBMwas formed by means of the Langmuir-Blodgett and Langmuir-Schaefer techniques, at a monolayer surface tension of 26 m Nm−1 in room temperature and on a deionized water subphase, which resulted in an average molecular area of 0.68–0.73 nm2. Fusion of transmembrane protein was investigated using Atomic Force Microscopy. Initial atomic force microscopy results demonstrate the ability to support lipid bilayers fused with transmembrane proteins across a porous silicon substrate. However, more control of the membrane’s surface tension using traditional membrane fusion techniques is required to optimize protein incorporation.