Supramolecular assemblies of a new series of gemini-type schiff base amphiphiles at the air/water interface: in situ coordination, interfacial nanoarchitectures, and spacer effect

Great interest has been devoted to the gemini amphiphiles because of their unique properties. In this article, we report some interesting properties of the interfacial films formed by a series of newly designed gemini amphiphiles containing the Schiff base moiety. This novel series of gemini amphiphiles with their Schiff base headgroups linked by a hydrophobic alkyl spacer (BisSBC18Cn, n = 2, 4, 6, 8, 10) could be spread to form stable monolayers and coordinated with Cu(Ac)(2) in situ in the monolayer. The alkyl spacer in the amphiphiles has a great effect on the regulation of the properties of the Langmuir monolayers. A maximum limiting molecular area was observed for the monolayers of the gemini amphiphile with the spacer length of hexa- or octamethylene groups. Both the monolayers on water and on the aqueous Cu(Ac)(2) subphase were transferred onto solid substrates, and different morphologies were observed for films with different spacers. Nanonail and tapelike morphologies were observed for amphiphile films with shorter spacers (n = 2 and 4) on the water surface. Wormlike morphologies were observed for gemini films with longer spacers of C(8) and C(10) when coordinated with Cu(Ac)(2). An interdigitated layer structure was supposed to form in the multilayer films transferred from water or the aqueous Cu(Ac)(2) subphase.     

Spacer-controlled aggregation and surface morphology of a selenacarbocyanine dye on gemini monolayers

The adsorption and aggregation of a selenacarbocyanine dye (3,3-disulfopropyl-9-methyl-selenacarbocyanine, SeCy) onto Langmuir monolayers of a series of gemini amphiphiles with different methylene spacers were investigated. When the monolayers of the gemini amphiphiles were spread on the dye-containing subphase, the dye could be easily adsorbed and aggregated onto the monolayers through the electrostatic and pi-pi interaction. The dye formed complexes with gemini amphiphiles and stacked as J-aggregates in all the transferred multilayers, regardless of the structure of gemini amphiphiles. However, the surface morphologies of the complex monolayers showed a significant dependence on the spacer length of the gemini amphiphiles and the temperature of the subphase. Nanorods were observed for the complex films with spacer lengths ranged from 4 to 10 methylenes. With the temperature of the subphases increased from 20 degrees C to 30 degrees C, aligned longer nanofibers were formed instead. Although both the gemini amphiphiles and the dye were achiral, strong circular dichroism (CD) signals were observed for the transferred complex films. However, the CD signals could be just opposite in different places of the transferred films, suggesting that a resolved enantiomeric micro/nanostructure coexisted in the films. On the other hand, for the complex film of the dye with the gemini amphiphile of two methylenes spacer, neither CD signal nor ordered surface morphologies were detected in any place of the film although the dye itself stilled formed J-aggregate in the film. It was suggested that regular nanoarchitectures and resolved chiral domains could be observed only when the spacer of gemini amphiphiles is comparative to the distance between the two SO3- groups in the dye.     

Regulation of aggregation and morphology of cyanine dyes on monolayers via gemini amphiphiles

The aggregation of dyes is of considerable importance in relating to their functions and applications. In this paper, we have investigated the regulation on the aggregation and morphology of two cyanine dyes, 3,3'-disulfopropyl-4,5,4',5'-dibenzo-9-methylthiacarbocyanine triethylammonium salt (MTC) and 3,3'-disulfopropyl-4,5,4',5'-dibenzo-9-phenylthiacarbocyanine triethylammonium salt (PTC), using a series of gemini amphiphiles (bis(2'-heptadecyl-3'-ethylimidazolium)-1,n-alkane dibromide, abbreviated as Gn, n=2, 4, 6, 8, 10). It has been found that both of the dyes could be adsorbed onto the monolayers of the gemini amphiphiles through the electrostatic and pi-pi interaction and stacked into H- or J-aggregate. The spacer of the gemini amphiphile showed good control over the aggregation of MTC: H-aggregate was favored when gemini amphiphiles with short spacer were applied, while J-aggregation was preferred in the case of longer spacer. Only J-aggregate was observed for PTC on gemini monolayer, regardless of the structure of the gemini amphiphiles. Interesting morphologies were observed for all the gemini/dye complex monolayers. Network structure and nanofibers were formed for the gemini/MTC films transferred below the plateau surface pressure and close to the collapse pressure, respectively. The ability of the complex monolayers to form nanofibers strongly depended on the component amphiphiles, G2>G4>G6, and no nanofibers were observed for G8/MTC and G10/MTC after the collapse. Only squared domains were observed for gemini/PTC monolayers. When both G2 and G10 were mixed, an individual control of the gemini amphiphiles over the aggregation of MTC in the complex monolayers was observed. The relationship among the spacer, dye structure, and aggregation was revealed.     

A photoluminescent switch based on the hybrid organized molecular films of decatungsteuropate and some amphiphiles

Hybrid organized molecular films composed of a polyoxometalate, decatungsteuropate (EuW(10)), and amphiphiles such as hexadecyltrimethylammonium bromide (CTAB), n-octadecylamine (ODA) and 4-hexadecylaniline (HDA) were fabricated by Langmuir-Blodgett (LB) technique and their photoluminescent properties were investigated. The hybrid films, which were formed through in situ complex formation at the air/water interface and subsequently transferred onto the solid substrate, were characterized by UV-vis, FT-IR, fluorescence, and AFM measurements. The transferred hybrid films showed red emission characteristic of the Eu(III) ion upon UV irradiation. The photoluminescence of the hybrid films was sensitive to the acid and base gases. When ODA/EuW(10) and HDA/EuW(10) hybrid films were exposed to HCl gas, their photoluminescence disappeared completely. Interestingly, the photoluminescence was recovered upon subsequent exposing the same film to NH(3) gas. Such process could be repeated many times and a switch based on these hybrid films was proposed. On the other hand, the photoluminescent intensity of CTAB/EuW(10) film decreased but never disappeared upon exposing to HCl gas. Similarly, the photoluminescence could also be partially recovered upon exposing to NH(3) gas. Detailed investigation on the spectral changes of the films revealed that the interaction between EuW(10) and CTAB and was different from EuW(10) with ODA or HDA, and protonation of amine group in ODA or HDA induced by HCl gas played an important role in realizing the "on" and "off" photoluminescence switch of the hybrid films.     

Design and interfacial behavior of two series of gemini amphiphiles with different charge positions based on imidazole moiety

Two series of gemini amphiphiles based on 2-heptadecylimidazole were designed. One is exo-BisImC17Cn (n=2, 4, 6, 8, 10), in which the positive charges are positioned on the outsides of the headgroups. The other is endo-BisImC17Cn (n = 2, 4, 6, 8, 10), whose positive charges are localized on the insides of the headgroups. The interfacial behavior at the air/water interface of these gemini amphiphiles was investigated in relation to the effect of the charge position and the spacer length. Monolayers of exo-BisImC17Cn show small differences in interfacial behavior when spread on water and aqueous Na2SO4 subphases. In contrast, significant distinctions were observed for molecules of endo-BisImC17Cn. The limiting areas of endo-BisImC17Cn monolayers on water are obviously larger than those on the aqueous Na2SO4 solution. While the limiting areas of the exo-BisImC17Cn monolayers increased monotonically with the spacer length, those of the endo-BisImC17C10 monolayer on Na2SO4 solution is obviously smaller than those of endo-BisImC17C6 and endo-BisImC17C8 monolayers, suggesting the wicket conformation of the alkyl chain in endo-BisImC17C10. On the other hand, both of the gemini amphiphiles could form complex monolayers with negatively charged TPPS at the air/water interface. The transferred complex multilayer films of the gemini amphiphiles/TPPS showed supramolecular chirality, although both of the gemini amphiphiles and TPPS are achiral. The exciton couplet was observed for the endo-BisImC17Cn/TPPS films, while no couplet was detected for the exo-BisImC17Cn/TPPS films. A reasonable comparison between the two series of geminis in relation to the effect of charge positions and the spacer lengths on the interfacial behavior and the supramolecular chirality was performed.     

Design and interfacial assembly of a new series of gemini amphiphiles with hydrophilic poly(ethyleneamine) spacers

A new series of gemini amphiphiles containing two Schiff base moieties linked by the poly(ethyleneamine) with different lengths were designed, and their interfacial assemblies were investigated. Condensed monolayers were obtained on nearly neutral subphase where the hydrophilic spacers were found to immerse into the subphase. On strong alkaline and acidic subphase, the headgroup and the spacer of the gemini amphiphiles underwent dissociation and protonation, respectively, resulting in the enlargement of the molecular areas. Flat and uniform domains were obtained for the monolayers from nearly neutral subphase; flower-like or dendritic domains were observed for the films transferred from strong acidic subphase. On the other hand, when an anionic tetrakis(4-sulfonatonphenyl)porphine (TPPS) was added into an acidic subphase, an in situ complex formation between the gemini amphiphiles and TPPS occurred. The complex monolayers were transferred onto solid substrate and TPPS existed predominantly as J-aggregate in the complex films. Due to the multisited positive charges in the spacer on acidic subphase, the complex films of gemini amphiphiles with TPPS appeared as short fiber or nanorod structures and formed two-dimensional (2D) conglomerate chiral domains.     

Synthesis and assembly of gold nanoparticles in organized molecular films of gemini amphiphiles

Generation and assembly of gold nanostructures were investigated in the organized molecular films of a series of gemini amphiphiles. The chloroauric acid, dissolved in the aqueous subphase, was incorporated into the monolayers of the gemini amphiphiles containing ethyleneamine spacers through an interfacial assembly. The in situ formed complex monolayers were transferred onto solid substrates, and gold nanoparticles were generated in the film by a chemical or photochemical reduction. Discrete gold nanoparticles with an absorption maximum at 550 nm were generated in the films by photoirradiation, while different gold nanostructures were obtained by chemical reduction. Depending on the chemical reductant, various shape and assembly of gold nanostructures were obtained. When reduced by hydroquinone, a tree-branched assembly of the nanoparticles was obtained and the film showed a broad band centered at around 900 nm. When NaBH 4 was applied, crooked nanowires or assembly of nanoparticles were obtained, depending on concentration, and the film showed absorption at 569 or 600 nm. Furthermore, by combining the photochemical and chemical reduction methods, i.e., the chloroaurate ion-incorporated film was initially irradiated with UV light and then subjected to chemical reduction, the optical absorption of the formed gold nanostructures can be regulated.     

Interfacial assemblies of cyanine dyes and gemini amphiphiles with rigid spacers: regulation and interconversion of the aggregates

A series of gemini amphiphiles with a pyridinium headgroup and rigid spacers were designed, and their interfacial assemblies with cyanine dyes, 3,3-disulfopropyl-9-methyl-selenacarbocyanine (SeCy) and 3,3-disulfopropyl-4,5,4',5'-dibenzo-9-methyl-thiocarbocyanine (MTC), through the air/water interface were investigated. Although the dyes have intrinsic tendencies to form J- or H-aggregates in aqueous solutions, their aggregation could be regulated in the complex films. Depending on the spacer, both J- and H-aggregates were formed for SeCy, whereas an H-aggregate with different absorption bands was obtained for MTC. Furthermore, the formed aggregates in the films could be reversibly switched by treating the complex films with HCl, NH3 gas, or water vapor. The J-aggregates of SeCy could be changed into H-aggregates and recovered through an alternative HCl/NH3 exposure in the films. The H-aggregate of the MTC film could be changed into J-aggregate upon exposure to HCl gas and subsequently put into air or NH 3 gas, and the thus-formed J-aggregate could be changed into H-aggregate under hot water vapor. In addition, such a reversible switch between different aggregates of MTC was only observed when the gemini amphiphiles with rigid spacers were applied. A possible explanation related to the protonation of the dye and the reorganizations in the film during the interconversion between different aggregates was proposed.     

Layer-by-layer assembly of Na9[EuW10O36]·32H2O and layered double hydroxides leading to ordered ultra-thin films: cooperative effect and orientation effect

Well-ordered, ultra-thin films (UTFs) based on the hybrid assembly of Na(9)[EuW(10)O(36)]·32H(2)O (denoted as EuW(10)) and exfoliated MgAl layered double hydroxide (LDH) monolayers have been fabricated by utilising a layer-by-layer (LBL) technique. The assembly process was monitored by UV/Vis absorption and fluorescence spectroscopy measurements to get a stepwise and regular growth of the UTFs upon increasing the deposited cycles. In the resulting (EuW(10)/LDH)(n) UTFs, the intercalation of EuW(10) anions into LDH monolayers allows the UTFs to retain their optical properties. Meanwhile, LDH monolayers provide EuW(10) with a confined and protective microenvironment to isolate them from each other between adjacent layers. The UTFs exhibit a periodic, long-range, ordered structure. Anisotropic luminescence spectroscopy measurements show that the (EuW(10)/LDHs)(n) UTFs display well-defined red luminescence with an anisotropy value, r, of about 0.15. Therefore, the cooperative and orientation effects between the host layers and guest anions play significant roles for the improved properties of the (EuW(10)/LDHs)(n) UTFs. This work could benefit the design and fabrication of novel electro-optical devices based on the UTFs of hybrid materials.     

Mode of interaction of two fluorinated-hydrogenated hybrid amphiphiles with dipalmitoylphosphatidylcholine (DPPC) at the air-water interface

Two-component Langmuir monolayers formed on 0.02M Tris buffer solution (pH 7.4) with 0.13M NaCl at 298.2K were investigated for two different fluorinated-hydrogenated hybrid amphiphiles (F6PH5PPhNa and F8PH5PPhNa or F6 and F8, respectively) with DPPC. Surface pressure (pi), surface potential (DeltaV) and dipole moment (mu( perpendicular)) as a function of molecular surface area (A) were measured by employing the Whilhelmy method and an ionizing electrode method. From the A- and DeltaV-X(F6) (or X(F8)) curves, partial molecular surface area (PMA) and apparent partial molecular surface potential (APSP) were determined as a function of surface mole fraction (X(Fn)) at discrete surface pressures. Then, the behavior of occupied surface areas and surface potentials of the respective components could be made clearer. Compressibility (C(s)), elasticity (C(s)(-1)), and excess Gibbs energy (DeltaG((ex))) as a function of X(F6) (or X(F8)) were estimated at definite pressures. These physico-chemical parameters were found to reflect the mechanical strength of monolayer films formed. The regular solution theory being applied to DeltaG((ex)), the activity coefficients (f) as well as the interaction parameter (I(p)) between DPPC and two hybrid amphiphiles in the binary monolayers were evaluated. I(p) values thus obtained indicated that F8 molecules interact more strongly with DPPC molecules than F6. Moreover, in order to better understand the morphological monolayer state, Langmuir-Blodgett (LB) films made from DPPC and fluorinated-hydrogenated hybrid amphiphiles were examined by atomic force microscopy (AFM). The miscibility of the two components in the monolayer state is evidenced by these thermodynamic quantities and AFM observations. Furthermore, AFM images demonstrated that F8 could more effectively disperse the ordered domains of DPPC than F6.     

Synthesis and characterization of amphiphilic fullerenes and their Langmuir-Blodgett films

We report here the synthesis and characterization of three amphiphilic fullerene derivatives and their Langmuir-Blodgett thin films. Two of the C(60) amphiphiles are mono-derivatives with a long alkyl chain terminated with either -COOH (2) or NH(2) (3) as the hydrophilic headgroup, and the third one (5) is designed to bear the same NH(2) group as 3 but with 10 additional hydrophobic alkyl chains grafted on the C(60) sphere (Scheme 1). These amphiphiles form stable, ordered monolayers at the air-water interface. The molecular packing at the air-water interface and the mean area per molecule are determined by pressure isotherms at room temperature. Hysteresis of pressure isotherms of side chain C(60) (5) shows complete reversibility upon compression and decompression, which suggests that side chains on the C(60) sphere inhibit formation of aggregates at the air-water interface. Comparative studies of all three amphiphiles allow us to better determine the interaction between C(60)'s and their self-assembly kinetics at the air-water interface. Monolayers of monoderivatized amphiphiles (2 and 3) were transferred successfully onto quartz substrates as Z-type multilayered Langmuir-Blodgett films, and monolayers of 5 were transferred as Y-type films. Detailed characterization of the multilayer films (Z-type deposition) prepared from amine-terminated C(60) (3) using X-ray and neutron reflectometry reveals staggering of C(60) spheres and a head-to-head (Y-type) structure presumably due to flipping and reattaching of C(60) amphiphiles to the previous underlying C(60) layer.     

Assembly and Characterization of Rare-earth-containing Polyoxometalate [Eu （P2Mo17O61）2]^17- and Poly（allylamine hydrochloride） Multilayer Films

The ultrathin multilayer films of rare-earth-containing polyoxometalate cluster K17[Eu(P2Mo17O61)2](EuPMo) and poly(allylamine hydrochloride) (PAH) have been prepared by the Layer-by-Layer(LbL) selfassembly method. The photoluminescent behavior of the films investigated at room temperature shows the Eu^3 characteristic emission pattern of ^5Do→^7FJ(J=1—4). The occurrence of the photoluminescent activity confirms the potential of creating luminescent multilayer films with polyoxometalates (POMs).     

Gemini peptide lipids with ditopic ion-recognition site. Preparation and functions as an inducer for assembling of liposomal membranes

Gemini amphiphiles having two peptide lipid units and a spacer group connected at the polar heads were synthesized. A gemini peptide lipid bearing l-histidyl residues, hydrophobic double-chain segments, and a tri(oxyethylene) spacer performed as an inducer of the reversible assembling of liposomal membranes through ditopic ion recognition toward transition metal ions and alkali metal ions. The vesicular assembling behavior induced by the gemini peptide lipids was sensitive to the structural difference in the amino acid residue and the spacer group of the lipids.     

Synthesis of nonionic reduced-sugar based bola amphiphiles and gemini surfactants with an α,ω-diamino-(oxa)alkyl spacer

Reduced-sugar based gemini surfactants with an α,ω-diamino-(oxa)alkyl spacer exhibit a rich pH-dependent aggregation behavior and are efficient DNA carriers in gene transfection. Herein, we describe an improved synthetic procedure for these amphiphiles. First, a series of novel nonionic bolaform amphiphiles with identical headgroups and α,ω-diamino-(oxa)alkyl spacers were synthesized by reductive aminations involving α,ω-diaminoalkanes and the appropriate sugars or aldehydes. The bolaform compounds were used as starting materials for the synthesis of the corresponding reduced-sugar based gemini surfactants in a reductive alkylation reaction employing a polymer-bound cyanoborohydride. A series of new gemini surfactants have been synthesized and characterized.     

Investigation in monolayers of double-chain fluorocarbon amphiphiles Effect of headgroups on molecular packing and interaction between hydrocarbon and fluorocarbon monolayers

The surface pressure-area diagrams of double-chain fluorocarbon amphiphiles with different headgroup compositions show that the amphiphiles arrange almost perpendicularly to the water subphase and the structure of headgroups exerts significant influence on the amphiphile packing. Strong hydrogen bonding and weak electrostatic interaction favor the formation of stable monolayers. Perfluorooctanoic acid (FOA) cannot form monolayer at water/air interface and can only form liquid monolayer in subphase of calcium nitrate solution. Complete phase separation of palmitic acid and a fluorocarbon amphiphile with shorter hydrocarbon spacer group, 1, could be demonstrated in monolayers by using the phase rule of Crisp. The creation of phase-separated monolayers is possible when the monolayer is composed of a mixture of palmitic acid and a fluorocarbon amphiphile with longer hydrocarbon spacer group, 2. It can be suggested that the miscibility of hydrocarbon amphiphiles with fluorocarbon amphiphiles is determined by the hydrocarbon fraction of fluorocarbon amphiphiles.     

A Polyaromatic Gemini Amphiphile That Assembles into a Well‐Defined Aromatic Micelle with Higher Stability and Host Functions

A gemini‐type amphiphilic molecule, constituted of two V‐shaped polyaromatic amphiphiles linked by a linear acetylene spacer, was synthesized. The gemini amphiphile assembles into a well‐defined aromatic micelle (ca. 2 nm in core diameter), providing higher stability in water even at low concentration (0.09 mm ) and high temperature (>130 °C). Unlike common gemini amphiphiles with aliphatic chains, the present amphiphile and its micellar assembly emit green and orange fluorescence (Φ_F=33 and 9 %), respectively. Despite strong and multiple π‐stacks of the polyaromatic panels of the amphiphiles, the water‐soluble gemini aromatic micelle incorporates medium‐size to large hydrophobic compounds into the frameworks. Interestingly, the guest binding capability toward large planar molecules was enhanced by more than two times through the pre‐encapsulation of spherical molecules in the cavity.     

Optical characterization of Eu3+ and Tb3+ ions doped zinc lead borate glasses

This paper reports on the spectral analysis of Eu3+ or Tb3+ ions (0.5 mol%) doped heavy metal oxide (HMO) based zinc lead borate glasses from the measurement of their absorption, emission spectra and also different physical properties. From the XRD, DSC profiles, the glass nature and glass thermal properties have been studied. The measured emission spectrum of Eu3+ glass has revealed five transitions (5D0-->7F0, 7F1, 7F2, 7F3 and 7F4) at 578, 591, 613, 654 and 702 nm, respectively, with lambdaexci=392 nm (7F0-->5L6). In the case of Tb3+:ZLB glass, four emission transitions such as (5D4-->7F6, 7F5, 7F4 and 7F3) that are located at 489, 542, 585 and 622 nm, respectively, have been measured with lambdaexci=374 nm. For all these emission bands decay curves have been plotted to evaluate their lifetimes and the emission processes that arise in the glasses have been explained in terms of energy level schemes.     

Preparation of microscopic and planar oil-water interfaces that are decorated with prescribed densities of insoluble amphiphiles

Langmuir monolayers (monolayers of insoluble molecules formed at the surface of water), and associated Langmuir-Blodgett/Schaefer monolayers prepared by transfer of Langmuir films to the surfaces of solids, are widely used in studies aimed at understanding the physicochemical properties of biological and synthetic molecules at interfaces. In this article, we report a general and facile procedure that permits transfer of Langmuir monolayers from the surface of water onto microscopic and planar interfaces between oil and aqueous phases. In these experiments, a metallic grid supported on a hydrophobic solid is used to form oil films with thicknesses of 20 mum and interfacial areas of 280 mum x 280 mum. Passage of the supported oil films through a Langmuir monolayer is shown to lead to quantitative transfer of insoluble amphiphiles onto the oil-water interfaces. The amphiphile-decorated oil-water interfaces hosted within the metallic grids (i) are approximately planar, (ii) are sufficiently robust mechanically so as to permit further characterization of the interfaces outside of the Langmuir trough, (iii) can be prepared with prescribed and well-defined densities of amphiphiles, and (iv) require only approximately 200 nL of oil to prepare. The utility of this method is illustrated for the case of the liquid crystalline oil 4-pentyl-4'-cyanobiphenyl (5CB). Transfer of monolayers of either dilauroyl- or dipalmitoylphosphatidylcholine (DLPC and DPPC, respectively) to the nematic 5CB-aqueous interface is demonstrated by epifluorescence imaging of fluorescently labeled lipid and polarized light imaging of the orientational order within the thin film of nematic 5CB. Interfaces prepared in this manner are used to reveal key differences between the density-dependent phase properties of DLPC and DPPC monolayers formed at air-water as compared to that of nematic 5CB-aqueous interfaces. The methodology described in this article should be broadly useful in advancing studies of the interfacial behavior of synthetic and biological molecules at liquid-liquid interfaces.     

PAMAM树枝状高分子自组装膜的微摩擦性能研究

自组装超薄膜的研究是近年来的热点课题，其制备与应用已深入到各个领域．研究表明，以高分子为构筑单元的有序结构超薄膜具有优良的微摩擦性能．在微摩擦学研究中，用C60作刚性基团，提高薄膜润滑材料的承载能力，已有不少报道．Tsukruk和Perry等分别研究了由C60组装形成的单层膜的微摩擦行为．薛群基等曾尝试在脂     

Preparation and characterization of polyion-complexed Langmuir-Blodgett films containing an NLO chromophore

Polyion complexes formed by monolayers of quaternary ammonium amphiphiles containing the 4-nitro-4'-alkoxy azobenzene chromophore spread at the surface of aqueous solutions of a number of anionic polyelectrolytes were investigated. In general, pi-A isotherms were found to depend on the nature of the polyion present in the subphase, with monolayers of complexes involving polycarboxylates tending to exhibit larger limiting areas than those formed with polysulfonates or polysulfates. Monolayers of the polyion complexes can be transferred to hydrophilic solid substrates to yield Z-type LB films, although some peeling off for more than 10 layers is an impediment. X-ray reflectivity measurements indicate that relatively smooth and uniform films are obtained up to about 10 layers. Average layer thicknesses are, however, significantly smaller than extended molecular lengths, implying that the amphiphiles are strongly inclined from the surface normal. Polarized FT-IR measurements also indicate poor molecular orientation perpendicular to the surface. Preliminary SHG measurements for LB films of two systems, 12Q/CMC-Na and 12Q/PAA, confirm the presence of noncentrosymmetric out-of-plane chromophore ordering. Stable signals are observed for elevated temperatures up to 130 degrees C and for a period of 4 months at room temperature. To the best of our knowledge, this represents the first report of stable SHG in LB films of polyion complexes.