Langmuir-Blodgett Multilayers Research Articles

Fundamental studies of molecular depth profiling using organic delta layers as model systems.

Alternating Langmuir-Blodgett multilayers of barium arachidate (AA) and barium dimyristoyl phosphatidate (DMPA) were used to elucidate the factors that control depth resolution in molecular depth profiling experiments. More specifically, thin (4.4 nm) layers of DMPA were embedded in relatively thick (~50 nm) multilayer stacks of AA, resulting in a well-defined delta-layer model system closely resembling a biological membrane. This system was subjected to a three-dimensional imaging depth profile analysis using a focused buckminsterfullerene (C60) cluster ion beam. The depth response function measured in these experiments exhibits similar features as those determined in inorganic depth profiling: namely, an asymmetric shape with quasi-exponential leading and trailing edges and a central Gaussian peak. The magnitude of the corresponding characteristic rise and decay lengths is found to be 5 and 16 nm, respectively, while the total half width of the response function characterizing the apparent depth resolution was about 29 nm. Ion-induced mixing is proposed to be largely responsible for the broadening, rather than topography, as determined by atomic force microscopy.

Columnar Self-Assembly and Alignment of Planar Carbenium Ions in Langmuir−Blodgett Films

Structural and optical properties of multilayer Langmuir-Blodgett (LB) films of two amphiphilic carbenium salts 2-didecylamino-6,10-bis(dimethylamino)-4,8,12-trioxatriangulenium hexafluorophosphate (ATOTA-1) and 2,6-bis(decylmethylamino)-10-dimethylamino-4,8,12-trioxatriangulenium hexafluorophosphate (ATOTA-2) are described. The LB films were prepared on lipophilic glass by standard vertical dipping. Grazing incidence X-ray diffraction (GIXD) measurements show that the planar organic cores, in spite of their positive charge, form closely packed columns with a repeating distance of ∼3.45 Å. Specular X-ray reflectivity (SXR) reveals the LB multilayers to consist of Y-type bilayers with thickness 31 Å for ATOTA-1 and 41 Å for ATOTA-2. This significant difference is ascribed to the different packing motifs of the alkyl chains in the two LB films. GIXD and polarized UV-vis absorption and emission spectroscopy show that the columnar aggregates in the LB films are oriented along the dipping direction. This alignment is attributed to shear effects during LB transfer. The main absorption band of the LB films is blue-shifted compared to that in solution, while the fluorescence is red-shifted by more than 100 nm. These findings suggest the presence of H-aggregates in agreement with the cofacial packing derived from the X-ray measurements. Polarized absorption spectroscopy with variable angle of incidence was used to resolve two perpendicular optical transitions in the visible range, one at 460 nm polarized perpendicular to the columnar direction, in the plane of the film, and one at 420 nm polarized along the film normal.

Molecular depth profiling of buried lipid bilayers using C(60)-secondary ion mass spectrometry.

An organic delta layer system made of alternating Langmuir-Blodgett multilayers of barium arachidate (AA) and barium dimyristoyl phosphatidate (DMPA) was constructed to elucidate the factors that control depth resolution in molecular depth profile experiments. More specifically, one or several bilayers of DMPA (4.4 nm) were embedded in relatively thick (51 to 105 nm) multilayer stacks of AA, resulting in a well-defined delta layer model system closely resembling a biological membrane. 3-D imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS) depth profile analysis was performed on this system using a focused buckminsterfullerene (C(60)) cluster ion beam. The delta layer depth response function measured in these experiments exhibits similar features as those determined in inorganic depth profiling, namely an asymmetric shape with quasi-exponential leading and trailing edges and a central Gaussian peak. The effects of sample temperature, primary ion kinetic energy, and incident angle on the depth resolution were investigated. While the information depth of the acquired SIMS spectra was found to be temperature independent, the depth resolution was found to be significantly improved at low temperature. Ion induced mixing is proposed to be largely responsible for the broadening, rather than topography, as determined by atomic force microscopy (AFM); therefore, depth resolution can be optimized using lower kinetic energy, glancing angle, and liquid nitrogen temperature.

Optimization of mixed Langmuir–Blodgett films of a water insoluble porphyrin in a calixarene matrix for optical gas sensing

The gas sensing capabilities of Langmuir–Blodgett (LB) mixed films of 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy)phenyl]-21H,23H-porphine (EHO) and p-tert-butylcalix[8]arene (C8A) have been studied in this work. Although EHO is known to be very sensitive to NO2 gas, this study demonstrates that the C8A matrix improves the sensing properties of the porphyrin molecules in the solid state. After the exposure to NO2 and the subsequent recovery, the UV–vis spectrum of a C8A:EHO film shows no aggregation of the porphyrin. In atomic force microscopy (AFM) images, C8A:EHO films appear with sharper surfaces than those made of pure EHO, allowing a better accessibility of the gas molecules to the active binding sites. Multilayer LB films of the C8A:EHO system ranging from 2 to 40 layers have been prepared to study their response to NO2 by UV–vis spectroscopy, and their kinetics reveal an important thickness dependence. Through the analysis of AFM images, it has been found that the surface roughness increases until the sample reaches 20 layers and then remains almost constant, which is related to the response time. The optimum film thickness has been found to be 20 layers, for which both the speed of response and the surface roughness are maximum.

Interaction between Langmuir and Langmuir−Blodgett Films of Two Calix[4]arenes with Aqueous Copper and Lithium Ions

The binding interactions between aqueous copper (Cu(2+)) and lithium (Li(+)) ions and Langmuir monolayers and Langmuir-Blodgett (LB) multilayers have been investigated by studying surface pressure-area (Pi-A) isotherms and surface potential-area (DeltaV-A) behavior in order to find the effective dipole moment, mu(perpendicular), of the calixarene molecules in the uncomplexed and complexed states. The orientation of both calix[4]arenes, namely, 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene and 5,17-(9H-fluoren-2-yl)methyleneamino)-11,23-di-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene, is such that the plane of the calix ring is parallel with the plane of the water surface regardless of the ion content of the subphase. The Gibbs equation was used to interpret the adsorption of ions with both calix[4]arenes as a function of the concentration. Effective dipole moments have been calculated from surface potential values using the Helmholtz equation. In this work, new LB films have been prepared employing two novel amphiphilic calix[4]arene derivatives bearing different upper rim substituents. Thus, the effect of modifiying the upper rim has been observed. The results have shown that these calixarenes may be useful components of ion sensors.

Highly Ordered and Stable Layered “Polymer Nanosheets” Constructed with Amorphous Side Chains and π−π Stacking of Functional Groups in Ternary Comb Copolymers

We have developed a highly stable, layered structure for ternary copolymers in Langmuir-Blodgett (LB) films at a nanometer scale, with substantial durability over the long-term. In these ternary copolymer LB films, amorphous side chains support the layered structure, and the distance between the layers is controlled at the nanometer scale by the composition of hydrogenated and fluorinated side chains. In the present study, the fine structures of newly synthesized ternary comb copolymers with a carbazole ring in the solid state and molecular orientations in the LB films were investigated using wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), surface pressure-area (pi-A) isotherms, in-plane and out-of-plane X-ray diffraction (XRD), and atomic force microscopy (AFM). The WAXD results identified two short-spacing peaks related to the formation of the subcells for both the fluorinated and hydrogenated side chains. Further, SAXS measurements indicated that these ternary copolymers formed a highly ordered layer structure. In addition, monolayers on the water surface of these ternary copolymers were highly condensed. From the results of in-plane XRD and AFM, it was determined that the side chains and side-chain crystals could not form phase-separated structures in two-dimensional films. These structural features may result from enhancement of pi-pi interactions between the arranged carbazole rings. The side chains of the copolymers in the two-dimensional films are apparently in a miscible state, and monolayers form a homogeneous amorphous surface because of cancellation of differences in van der Waals forces between the two types of side chains. As a result, formation of a highly ordered layer structure in copolymer films having substantial durability over the long term is realized because amorphous side chains support the layer structure in the LB multilayers. Further, control of long spacing at a subnanometer level becomes possible due to changes in the tilt angle of the side chains, depending on their fluorocarbon content.

Preparation of a Nickel Ion Containing Langmuir–Blodgett Multilayer and an Ultra-Thin Nickel Film Deposited on an Interpenetrating Polymer Network Substrate

The nickel ion containing Langmuir–Blodgett (LB) multilayer was prepared by transferring nickel acetate, spread on the surface of a sub-phase of ultra-pure water and stearic acid–chloroform mixture, onto an interpenetrating polymer network (IPN) substrate. The substrate was prepared by dip-pulling a hydrophilic silicon wafer or a glass plate into precursors, followed by solidification at room temperature, in order to create an ultra-thin and uniform surface for metal deposition. The multilayer was then converted into an ultra-thin nickel film after chemical reduction by 0.01 mol/l sodium borohydride. The surface pressure of the monolayer and dipping speed of substrate were determined by measuring the transfer coefficient. Fourier transform infrared spectroscopy (FT-IR) was used to investigate the interactions of the nickel ions with the IPN during the multilayer deposition on substrate, and the metal transformations of nickel ion in the ultra-thin film. The shifted peak location for –C=O verified the interactions between the IPN and the nickel ion and the transformation of the nickel ion by reduction. Further reduction caused the organic phase to dissolve, resulting in most of it being removed from the multilayer. The surface morphologies of the LB multilayer were detected by atomic force microscopy (AFM). Compared with the IPN, which formed a uniform and flat film, within a range of nanometers, the Ni/IPN multilayer and Ni ultra-thin film both showed some surface fluctuations, although these were still within nanometer range. The roughness of the nickel ion containing multilayer and the ultra-thin nickel film was 1.123 nm and 0.773 nm with a maximum height of 12.451 nm and 14.933 nm, respectively, which were larger than that of pure IPN substrate of 0.593 nm with the max height of 6.795 nm.

Detection of catechol using mixed Langmuir–Blodgett films of a phospholipid and phthalocyanines as voltammetric sensors

The combination of metallic phthalocyanines (MPcs) and biomolecules has been explored in the literature either as mimetic systems to investigate molecular interactions or as supporting layers to immobilize biomolecules. Here, Langmuir-Blodgett (LB) films containing the phospholipid dimyristoyl phosphatidic acid (DMPA) mixed either with iron phthalocyanine (FePc) or with lutetium bisphthalocyanine (LuPc(2)) were applied as ITO modified-electrodes in the detection of catechol using cyclic voltammetry. The mixed Langmuir films of FePc + DMPA and LuPc(2) + DMPA displayed surface-pressure isotherms with no evidence of molecular-level interactions. The Fourier Transform Infrared (FTIR) spectra of the multilayer LB films confirmed the lack of interaction between the components. The DMPA and the FePc molecules were found to be oriented perpendicularly to the substrate, while LuPc(2) molecules were randomly organized. The phospholipid matrix induced a remarkable electrocatalytic effect on the phthalocyanines; as a result the mixed LB films deposited on ITO could be used to detect catechol with detection limits of 4.30 × 10(-7) and 3.34 × 10(-7) M for FePc + DMPA and LuPc(2) + DMPA, respectively. Results from kinetics experiments revealed that ion diffusion dominated the response of the modified electrodes. The sensitivity was comparable to that of other non-enzymatic sensors, which is sufficient to detect catechol in the food industry. The higher stability of the electrochemical response of the LB films and the ability to control the molecular architecture are promising for further studies with incorporation of biomolecules.

PREPARATION OF NICKEL ULTRATHIN FILM BY THE LANGMUIR–BLODGETT TECHNIQUE AND CHEMICAL REDUCTION

The nickel ion containing Langmuir–Blodgett (LB) multilayer was prepared by transferring first dissolving nickel acetate and the solution was poured into a subphase of ultrapure water and stearic acid-chloroform. The resultant mixture was then spread onto a hydrophilic water or glass plate. Then the multilayer was converted into nickel ultrathin film after chemical reduction by sodium borohydride. The optimized parameters for monolayer formation, such as concentration of subphase, pH value, barrier speed and standing time, were determined by the measurement of the surface pressure–surface area (Π–A) isotherms. The expended areas after deposition with nickel ions inferred the interaction of stearic acid with nickel ion during the formation of monolayer at air–water interface. The optimized parameters for multilayer deposition, such as surface pressure and dipping speed were determined by the measurement of the transfer coefficient. The Fourier transform infrared spectroscopy (FTIR) was used to investigate the interactions of nickel ions with stearic acid at air–water interface and in nickel ion/stearic acid LB film, as well as the metal transformations of nickel ion in ultrathin film. The disappearance of peak at 1689 cm-1 verified the interactions between stearic acid and nickel ion. The further reduction made the organic phase dissolve and remove from the multilayer mostly. The surface morphologies of the LB multilayer and ultrathin film after reduction were detected by atomic force microscopy (AFM). A uniform and flat surface of nickel ultrathin film within nanometer ranges were obtained after reduction. The particle sizes of nickel were approximately 50 nm.

Orientational Behavior of Ionic Liquid Crystal Polymers and Their Nonionic Family

Multilayered Langmuir-Blodgett (LB) films were prepared from the monolayers of an ionic liquid crystalline azo-polymer (IP-4) and a nonionic liquid crystalline azo-polymer (NP-4). The multilayer structures in the LB films were completely disturbed by UV light irradiation. However, the periodic layer orderings in the LB films were rebuilt upon a subsequent visible light irradiation. Although NP-4 exhibits a nematic phase in the bulk state at room temperature, the consequent double layered structure with a homeotropic alignment in the LB film of NP-4 was very similar to the smectic layered structures of IP-4.

Taking Advantage of Electrostatic Interactions To Grow Langmuir−Blodgett Films Containing Multilayers of the Phospholipid Dipalmitoylphosphatidylglycerol

The use of phospholipids as mimetic systems for studies involving the cell membrane is a well-known approach. In this context, the Langmuir and Langmuir-Blodgett (LB) methods are among the main techniques used to produce ordered layers of phospholipids structured as mono- or bilayers on water subphase and solid substrates. However, the difficulties of producing multilayer LB films of phospholipids restrict the application of this technique depending on the sensitivity of the experimental analysis to be conducted. Here, an alternative approach is used to produce LB films containing multilayers of the negative phospholipid dipalmitoylphosphatidylglycerol (DPPG). Inspired by the electrostatic layer-by-layer (LbL) technique, DPPG multilayer LB films were produced by transferring the DPPG Langmuir monolayers from the water subphase containing low concentrations of the cationic polyelectrolyte poly(allylamine hydrochloride) (PAH) onto solid substrates. Fourier transform infrared (FTIR) absorption spectroscopy revealed that the interactions between the NH(3)(+) (PAH) and PO(4)(-) (DPPG) groups might be the main driving forces that allow growth of these LB films. Besides, ultraviolet-visible (UV-vis) absorption spectroscopy showed that the multilayer LB films can be grown in a controlled way in terms of thickness at nanometer scale. Cyclic voltammetry showed that DPPG and PAH are more packed in the LB than LbL films. The latter finding is related to the distinct molecular architecture of the films since DPPG is structured as monolayers in the LB films and multilamellar vesicles in the LbL films. Despite the interaction with PAH, cyclic voltammetry also showed that DPPG retains its biological activity in LB films, which is a key factor since this makes DPPG a suitable material in sensing applications. Therefore, multilayer LB films were deposited onto Pt interdigitated electrodes forming sensing units, which were applied in the detection of a phenothiazine compound [methylene blue (MB)] using impedance spectroscopy. The performance of DPPG in single-layer and multilayer LB films was compared to the performance of sensing unities composed of DPPG in single-layer and multilayer LbL films, showing the importance of both the thickness and the molecular architecture of the thin films. As found in a previous work for LbL films, the high sensitivity reached by these sensing units is intimately related to changes in the morphology of the film as evidenced by the micro-Raman technique. Finally, the interaction between MB and the (DPPG+PAH) LB films was complemented by pi-A isotherms and surface-enhanced resonance Raman scattering (SERRS).

Dependence of mesoscopic growth on molecular configuration in Langmuir–Blodgett multilayers

Systematic studies by atomic force microscopy and X-ray reflectivity of three monolayer Langmuir–Blodgett films of M-Stearate (M = Cd, Zn, Mn) show change in surface morphology and growth mode with change in metal ions in the headgroup. Growth proceeds via Volmer Weber mode in CdSt, Stranski–Krastanov mode in ZnSt and Frank Van der Merwe mode in MnSt, as ascertained from fractal dimensions and out-of-plane density profiles. This is closely related with increase in number of metal ions incorporated per headgroup with change in metal ions in the order Cd, Zn and Mn. A preliminary correlation with metal atomic number is noted.

Sputtering of Langmuir–Blodgett multilayers by keV C 60 projectiles as seen by computer simulations

Fundamental processes induced in a thick organic system composed of long, well-organized linear molecules by an impact of 5–20 keV C 60 are investigated. The organic system is represented by Langmuir–Blodgett multilayers formed from bariated molecules of arachidic acid. The thickness of the system varies between 2 and 16 nm. Coarse-grained molecular dynamics computer simulations are applied to investigate the energy transfer pathways and sputtering yields as a function of the kinetic energy of the projectile and the thickness of the organic overlayer. The results indicate that an impact of keV C 60 projectiles leads to significant ejection of organic material. The efficiency of desorption increases with the kinetic energy of the projectile for a given layer thickness. For a constant primary kinetic energy, the sputtering yield goes through a maximum and finally saturates as the LB layer becomes thicker. Such behaviour is caused by a competition between signal enhancement due to increasing number of organic molecules and signal decrease due to lowering of the amount of the primary energy being backreflected into the organic overlayer by the receding organic/metal interface as the layer is getting thicker. When the sample thickness becomes much larger than the penetration depth of the projectile, the sputtering yield is independent of thickness. The deposited energy is channelled by an open and ordered molecular structure, which leads to abnormally long projectile penetration and ion-induced damage.

Molecular dynamics simulations of sputtering of Langmuir-Blodgett multilayers by keV C(60) projectiles.

Coarse-grained molecular dynamics computer simulations are applied to investigate fundamental processes induced by an impact of keV C(60) projectile at an organic overlayer composed of long, well-organized linear molecules. The energy transfer pathways, sputtering yields, and the damage induced in the irradiated system, represented by a Langmuir-Blodgett (LB) multilayers composed from molecules of bariated arachidic acid, are investigated as a function of the kinetic energy and impact angle of the projectile and the thickness of the organic system. In particular, the unique challenges of depth profiling through a LB film vs. a more isotropic solid are discussed.The results indicate that the trajectories of projectile fragments and, consequently, the primary energy can be channeled by the geometrical structure of the overlayer. Although, a similar process is known from sputtering of single crystals by atomic projectiles, it has not been anticipated to occur during C(60) bombardment due to the large size of the projectile. An open and ordered molecular structure of LB films is responsible for such behavior. Both the extent of damage and the efficiency of sputtering depend on the kinetic energy, the impact angle, and the layer thickness. The results indicate that the best depth profiling conditions can be achieved with low-energy cluster projectiles irradiating the organic overlayer at large off-normal angles.

Chemistry at Air/Water Interface versus Reaction in a Flask: Tuning Molecular Conformation in Thin Films

Atomic force microscopy and X-ray reflectivity studies of cobalt stearate Langmuir-Blodgett (LB) films (CoStp) deposited from a preformed bulk sample on quartz substrates showed formation of a Volmer-Weber type monolayer but no multilayers as compared to the excellent multilayers of cobalt stearate films (CoStn) deposited at the air/water interface by the usual LB technique, in spite of both showing bidentate bridging type coordination of cobalt ions with the carboxylate group. The difference is attributed to existence of different headgroup conformers, observed from Fourier transform infrared (FTIR) studies. The CoStp films had a higher energy 'boat' conformation with linear O-Co-O linkage, whereas CoStn formed a low energy conformer with a bent O-Co-O configuration (bond angle of 105 degrees). Present results support the necessity of bidentate bridging coordination in multilayer deposition, but rejects its sufficiency by bringing out the crucial role played by air/water interface. Differences in surface pressure-molecular area isotherms and hydrocarbon tail-tail interactions (evident from FTIR spectra) of the films support the above statement. Methyl-methyl interactions observed in CoStn samples suggest hierarchy of supramolecular chemistry at the air/water interface in tuning the C-O-Co bond angle essential to satisfy the wetting condition with the substrate and subsequently form LB multilayers.

Sputtering of thin films of bariated molecules of arachidic acid by large noble gas clusters

Coarse-grained molecular dynamics computer simulations have been employed to investigate the sputtering process of a multilayer organic system composed of long, well-organized linear molecules induced by an impact of slow clusters composed of large number of noble gas atoms. The organic system is represented by Langmuir–Blodgett multilayers formed from bariated molecules of arachidic acid. The sputtering yield, surface modifications and the angular distributions of ejected species have been analyzed as a function of the kinetic energy of an Ar 872 cluster projectile and the thickness of the deposited multilayer. It has been shown that the physics of ejection by these large and slow clusters is distinct from the ejection events stimulated by the popular SIMS clusters: C 60, Au 3 and SF 5. The organic molecules are not ejected by interaction with the energized substrate but by direct interactions with the projectile atoms.

Ordered conducting polymer multilayer films and its application for hole injection layers in organic light-emitting devices

We reported a controlled architecture growth of layer-ordered multilayer film of poly(3,4-ethylene dioxythiophene) (PEDOT) via a modified Langmuir–Blodgett (LB) method. An in situ polymerization of 3,4-ethylene dioxythiophene (EDOT) monomer in multilayer LB film occurred for the formation of ordered conducting polymer embedded multilayer film. The well-distribution of conducting polymer particles was characterized by secondary-ion mass spectrometry (SIMS). The conducting film consisting of ordered PEDOT ultrathin layers was investigated as a hole injection layer for organic light-emitting diodes (OLEDs). The results showed that, compared to conventional spin-coating PEDOT film and electrostatic self-assembly (ESA) film, the improved performance of OLEDs was obtained after using ordered PEDOT LB film as hole injection layer. It also indicated that well-ordered structure of hole injection layer was attributed to the improvement of OLED performance, leading to the increase of charged carrier mobility in hole injection layer and the recombination rate of electrons and holes in the electroluminescent layer.

Langmuir–Blodgett films of C 60 and C 60O on Silicon: Islands, rings and grains

We show that monolayer-high islands of C 60 and C 60O can be transferred from Langmuir films on a water or phenol sub-phase to oxide-terminated Si(111) substrates. Faceted islands, in some cases incorporating a foam-like morphology reminscent of that previously observed for Langmuir films at the water–air interface using Brewster angle microscopy, are formed and transferred using small amounts (100–400 μl) of low concentration (of order 10 − 5 M) solutions of C 60 (or C 60O) with low target pressures (~ 10 mN/m). However, worm-like monolayer domains are also observed under identical experimental conditions, indicating the key role that inhomogeneous solvent evaporation plays in the formation of two-dimensional fullerene aggregates on the subphase surface. While Langmuir–Blodgett multilayers of C 60 and C 60O are both granular, there are significant morphological differences observed between the molecular thin films. In particular, C 60O multilayers contain a relatively high density of ring (or “doughnut”) features with diameters in the 100–300 nm range which are not observed for C 60. We attribute the origin of these features to dipolar or hydrogen bonding-mediated interactions between the C 60O molecules at the water surface.

On the preparation of ultrathin tin dioxide by Langmuir–Blodgett films deposition

Langmuir–Blodgett (LB) technique has been used for the preparation of ultrathin tin dioxide film. Octadecyl amine (ODA) forms a stable complex with sodium stannate at the air–water interface and ODA–stannate complex has been deposited on solid substrate by LB technique. Multilayer LB films have been decomposed at 300 °C and 600 °C for 2–3 h to form thin metal oxide films on various substrates. The oxide films have been characterized by various techniques such as X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, UV–visible spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy, scanning electron microscopy, capacitance–voltage and current–voltage measurements. XRD measurements show the formation of crystalline structure of SnO 2 after heating of the multilayer LB film at a temperature of 600 °C. FTIR and XPS measurements indicate that ODA molecule is almost removed after heating at 300 °C and pure SnO 2 has been formed when it is heated at 600 °C. Current and capacitance voltage measurements on Si/SnO 2/gold and quartz/SnO 2/gold structure show the formation of semiconducting SnO 2 thin films.

Depth resolution during C60+ profiling of multilayer molecular films.

Time-of-flight secondary ion mass spectrometry is utilized to characterize the response of Langmuir-Blodgett (LB) multilayers under the bombardment by buckminsterfullerene primary ions. The LB multilayers are formed by barium arachidate and barium dimyristoyl phosphatidate on a Si substrate. The unique sputtering properties of the C60 ion beam result in successful molecular depth profiling of both the single component and multilayers of alternating chemical composition. At cryogenic (liquid nitrogen) temperatures, the high mass signals of both molecules remain stable under sputtering, while at room temperature, they gradually decrease with primary ion dose. The low temperature also leads to a higher average sputter yield of molecules. Depth resolution varies from 20 to 50 nm and can be reduced further by lowering the primary ion energy or by using glancing angles of incidence of the primary ion beam.