Structural characterization of a spin-assisted colloid-polyelectrolyte assembly: stratified multilayer thin films

The assembly of polyelectrolytes and gold nanoparticles yields stratified multilayers with very low roughness and high structural perfection. The films are prepared by spin-assisted layer-by-layer self-assembly (LbL) and are characterized by X-ray reflectivity (XRR), UV-vis spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM). Typical structures have four repeat units, each of which consists of eight double layers (DL) of poly(sodium 4-styrenesulfonate)/poly(allylamine hydrochloride), one monolayer of gold nanoparticles (10 nm diameter), and another layer of poly(allylamine hydrochloride). XRR scans show small-angle Bragg peaks up to seventh order, evidencing the highly stratified structure. Pronounced Kiessig fringes indicate a low global roughness, which is confirmed by local AFM measurements. TEM images corroborate the layered structure in the growth direction and nicely show the distinct separation of the individual particle layers. An AFM study reveals the lateral gold particle distribution within one individual particle layer. Interestingly, the spin-assisted deposition of polyelectrolytes reduces the roughness induced by the particle layers, leading to self-healing of roughness defects and a rather perfect stratification.     

Comparative characterisation by atomic force microscopy and ellipsometry of soft and solid thin films

Ellipsometry and atomic force microscopy (AFM) were used to study the film thickness and the surface roughness of both ‘soft’ and solid thin films. ‘Soft’ polymer thin films of polystyrene and poly(styrene–ethylene/butylene–styrene) block copolymer were prepared by spin‐coating onto planar silicon wafers. Ellipsometric parameters were fitted by the Cauchy approach using a two‐layer model with planar boundaries between the layers. The smooth surfaces of the prepared polymer films were confirmed by AFM. There is good agreement between AFM and ellipsometry in the 80–130 nm thickness range. Semiconductor surfaces (Si) obtained by anisotropic chemical etching were investigated as an example of a randomly rough surface. To define roughness parameters by ellipsometry, the top rough layers were treated as thin films according to the Bruggeman effective medium approximation (BEMA). Surface roughness values measured by AFM and ellipsometry show the same tendency of increasing roughness with increased etching time, although AFM results depend on the used window size. The combined use of both methods appears to offer the most comprehensive route to quantitative surface roughness characterisation of solid films. Copyright © 2007 John Wiley & Sons, Ltd.     

Controlled nitroxide-mediated styrene surface graft polymerization with atmospheric plasma surface activation

Polymer layer growth by free radical graft polymerization (FRGP) and controlled nitroxide-mediated graft polymerization (NMGP) of polystyrene was achieved by atmospheric pressure hydrogen plasma surface activation of silicon. Kinetic polystyrene layer growth by atmospheric pressure plasma-induced FRGP (APPI-FRGP) exhibited a maximum surface-grafted layer thickness (125 A after 20 h) at an initial monomer concentration of [M] 0 = 2.62 M at 85 degrees C. Increasing both the reaction temperature ( T = 100 degrees C) and initial monomer concentration ([M] 0 = 4.36 M) led to an increased initial film growth rate but a reduced polymer layer thickness, due to uncontrolled thermal initiation and polymer grafting from solution. Controlled atmospheric pressure plasma-induced NMGP (APPI-NMGP), using 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), exhibited a linear increase in grafted polystyrene layer growth with time due to controlled surface graft polymerization as well as reduced uncontrolled solution polymerization and polymer grafting, resulting in a polymer layer thickness of 285 A after 60 h at [TEMPO] = 10 mM, [M] 0 = 4.36 M, and T = 120 degrees C. Atomic force microscopy (AFM) surface analysis demonstrated that polystyrene-grafted surfaces created by APPI-NMGP exhibited a high surface density of spatially homogeneous polymer features with a low root-mean-square (RMS) surface roughness ( R rms = 0.36 nm), similar to that of the native silicon surface ( R rms = 0.21 nm). In contrast, polymer films created by APPI-FRGP at [M] 0 = 2.62 M demonstrated an increase in polymer film surface roughness observed at reaction temperatures of 85 degrees C ( R rms = 0.55 nm) and 100 degrees C ( R rms = 1.70 nm). The present study concluded that the current approach to APPI controlled radical polymerization may be used to achieve a grafted polymer layer with a lower surface roughness and a higher fractional coverage of surface-grafted polymers compared to both conventional FRGP and APPI-FRGP.     

Electrosynthesis of well-organized nanoporous poly(3,4-ethylenedioxythiophene) by nanosphere lithography

The electrodeposition of poly(3,4-ethylenedioxythiophene) (PEDOT) films from aqueous surfactant solution through a two-dimensional poly(styrene) (PS) template onto indium tin oxide (ITO) substrate has been investigated. The polymer grows in the interstitial spaces of the self-assembled PS spheres which were subsequently removed by dissolution in tetrahydrofuran (THF). Surface characterization by scanning electron microscopy (SEM) and atomic force microscopy (AFM) reveals that two-dimensional nanoporous honeycomb PEDOT structures can easily be obtained by using PS spheres of different sizes. Gold electrodeposition onto the nanostructured PEDOT electrode was investigated and SEM images show preferential formation of nanoparticles (NP) on the wall and the rim of the PEDOT film but metal clusters inside the pores are also observed.     

Preparation of monomodal polyelectrolyte complex nanoparticles of PDADMAC/poly(maleic acid-alt-alpha-methylstyrene) by consecutive centrifugation

We report on the refinement of anionic and cationic nanoparticles of nonstoichometric polyelectrolyte complexes (PEC) by consecutive centrifugation, which was studied by dynamic light scattering (DLS), atomic force microscopy (AFM), colloid titration and infrared spectroscopy (IR). PEC dispersions were prepared by mixing poly(diallyldimethylammonium chloride) (PDADMAC) and sodium poly(maleic acid-alt-alpha-methylstyrene) (PMA-MS) at the monomolar mixing ratio of n-/n+ = 1.50 (anionic PEC) and 0.66 (cationic PEC), respectively, and the polymer concentration of c(POL) = 0.002 M. The particle size (Rh), titrable charge amount, and IR spectra were determined for both dispersions in the original state, after the first centrifugation and after the second centrifugation. Freshly prepared PEC dispersions contained two different particle sizes: around 10-25 nm (small particles) and around 100 nm (large particles). Consecutive centrifugation of freshly prepared PEC dispersions resulted in the separation of highly charged excess polyelectrolyte (PEL) and small PEC particles from a low charged coacervate phase of the desired larger PEC particles. After the second centrifugation, the coacervate phase of both dispersions PEC-1.50 and PEC-0.66 consisted of monomodal particles sizing around 100 nm. These results were supported by AFM measurements on the respective dispersions deposited on glass plates. PEC-1.50 particles tended to adopt slightly smaller sizes ( approximately 90 nm) in comparison to PEC-0.66 ones (approximately 110 nm). No significant influence of the PDADMAC molecular weight on the particle size was found. IR spectroscopy showed changes in the environment of the carboxylate groups of PMA-MS by consecutive centrifugation. The centrifuged PEC-1.50 dispersions showed remarkable long-term stability over more than a year. The high macroscopic stability of the studied PEC dispersions is presumably due to repulsive electrostatic interparticle interactions and attractive hydrophobic intraparticle interaction. The introduced monomodal PEC particles might be projected as latex analogues or as nanocarriers for drugs and proteins.     

Atomically flat gold on elastomeric substrate

We present a procedure to fabricate extremely smooth Au films supported on thin elastomeric (PDMS) substrates. Minimum rms roughness and largest grain size are obtained using Si wafers, coated with native oxide and release layers, as templates for the growth of thermally evaporated Au films. The wafers are held at a temperature of 300 degrees C during deposition. The Au films, up to 200 nm thick, are then transferred onto poly(dimethylsiloxane) substrates which have been previously surface-functionalized with a (3-mercaptopropyl)trimethoxysilane adhesion layer. The resulting Au films have been found by AFM to be extremely smooth with rms-roughness 2.5-4 angstroms and to exhibit a crystalline morphology with flat grains >500 nm in size. Thinner films, down to 20 nm, are grown at lower temperature and are comparably smooth, but with a loss in crystalline morphology. We compare the results of this optimized procedure with other gold films grown on mica sheets as templates and to those produced using Ti-O-Si interfacial chemistry.     

Amphiphilic polymers as pseudotemplates in the synthesis of metal sols

The effects of poly(ethylene glycol) and its amphiphilic polymers on the products of copper ion reduction in aqueous solutions are studied. Whereas coarse metal dispersions are formed in poly(ethylene glycol) solutions, stable sols of metal nanoparticles with diameters of 2 nm and above are produced in the presence of poly(ethylene glycol monolaurate) and poly(ethylene glycol monostearate). A poly(ethylene glycol)-poly(propylene glycol) block copolymer (Pluronic) also stabilizes copper nanoparticles; however, the interaction product of this copolymer with nanoparticles forms a precipitate. According to the electron microscopy data, sol particles comprise polymer micelles containing included copper nanoparticles.     

Molecular ordering and 2D conductivity in ultrathin poly(3-hexylthiophene)/gold nanoparticle composite films

This paper reports the first comparison of the structure and electrical conductivity properties of spin cast (SC) and Langmuir-Schaeffer (LS) films of regioregular poly(3-hexylthiophene) (P3HT). In addition, the effect of incorporating highly monodisperse Au nanoparticles (NPs), with a core diameter of approximately 5 nm, into SC and LS P3HT films is described. A detailed picture of molecular organization in the films has been obtained using ultraviolet-visible absorption spectroscopy, atomic force microscopy, field-emission scanning electron microscopy, X-ray diffraction, and X-ray reflectivity. Film morphology was correlated with pseudo-two-dimensional conductivity measured using scanning electrochemical microscopy, with P3HT in the semiconducting regime. It was found that SC films, which were slightly thicker than those formed with the LS technique, exhibited greater organization. This resulted in an order of magnitude higher lateral conductivity for the SC films. Inclusion of Au NPs (50 wt %) into both SC and LS films resulted in the formation of uniform and relatively flat (rms roughness approximately 1 nm) composite films. Surprisingly, the addition of NPs did not disrupt the characteristic crystal structure found for the native P3HT films. The effect of Au NPs on film lateral conductivity was found to be determined by the distribution of Au NPs within the polymer, which varied significantly between SC and LS films. Whereas Au NPs aggregated into hexagonally packed clusters in SC films, NPs in LS films were predominantly uniformly distributed between the lamella bilayer. It was found that, while the inclusion of Au NPs caused the lateral conductivity to decrease in SC films, in LS films, the lateral conductivity increased by a factor of 2.     

Thickness and morphology of polyelectrolyte coatings on silica surfaces before and after protein exposure studied by atomic force microscopy

Analyte–wall interaction is a significant problem in capillary electrophoresis (CE) as it may compromise separation efficiencies and migration time repeatability. In CE, self-assembled polyelectrolyte multilayer films of Polybrene (PB) and dextran sulfate (DS) or poly(vinylsulfonic acid) (PVS) have been used to coat the capillary inner wall and thereby prevent analyte adsorption. In this study, atomic force microscopy (AFM) was employed to investigate the layer thickness and surface morphology of monolayer (PB), bilayer, (PB-DS and PB-PVS), and trilayer (PB-DS-PB and PB-PVS-PB) coatings on glass surfaces. AFM nanoshaving experiments providing height distributions demonstrated that the coating procedures led to average layer thicknesses between 1 nm (PB) and 5 nm (PB-DS-PB), suggesting the individual polyelectrolytes adhere flat on the silica surface. Investigation of the surface morphology of the different coatings by AFM revealed that the PB coating does not completely cover the silica surface, whereas full coverage was observed for the trilayer coatings. The DS-containing coatings appeared on average 1 nm thicker than the corresponding PVS-containing coatings, which could be attributed to the molecular structure of the anionic polymers applied. Upon exposure to the basic protein cytochrome c, AFM measurements showed an increase of the layer thickness for bare (3.1 nm) and PB-DS-coated (4.6 nm) silica, indicating substantial protein adsorption. In contrast, a very small or no increase of the layer thickness was observed for the PB and PB-DS-PB coatings, demonstrating their effectiveness against protein adsorption. The AFM results are consistent with earlier obtained CE data obtained for proteins using the same polyelectrolyte coatings.     

A careful examination of the adsorption step in the alternate layer-by-layer assembly of linear polyanion and polycation

In order to elaborate alternate layer-by-layer assembly as a means to prepare ultrathin films, details of conventional polyion assemblies have been quantitatively analyzed by quartz crystal microbalance (QCM) technique with the aid of scanning electron microscopy (SEM) and atomic force microscopy (AFM). The alternate adsorption of poly(styrenesulfonate) (PSS) and poly(allylamine) (PAM) onto oppositely-charged surfaces displayed the pseudo first-order kinetics and was saturated within 10–20 min at pH 3 and 22°C. It was revealed that drying at every step increased the thickness of adsorbed films due to enhanced surface roughness of the films. Therefore, frequent drying is not profitable for preparing films in a good quality. Non-contact AFM observation revealed that drying of the film with nitrogen stream, forced polymer chains to align to one direction with increasing surface roughness. In contrast, water washing between the consecutive adsorptions was effective for successful alternate adsorption. About 10% of an adsorbed polyion layer was removed by 5-min water washing probably due to removal of the loosely-attached materials.     

Flat-on lamellae in spin-coated, stable films of poly(propylene azelate)

Thin films (5-500 nm thick) of the linear aliphatic polyester (3,7) poly(propylene azelate) (PPAz) were prepared by spin-coating of CHCl(3) polymer solutions with different polymer concentrations. The morphology and structure of the spin-coated thin films were investigated by atomic force microscopy (AFM) and by grazing incidence wide-angle X-ray scattering (GIWAXS) techniques. AFM revealed the continuous nature of the flat, spherulitic films which are stable against dewetting even for polymer coatings as thin as 15 nm. GIWAXS patterns revealed a high crystal orientation of the films. A sharp reflection on the meridian whose spacing is related to the polymer chain unit length (c-axis) supports the presence of flat-on lamellae morphology in the whole range of film thicknesses investigated. The flat-on lamellae morphology is also supported by AFM images. A triclinic unit cell with the c*-axis perpendicular to the substrate is proposed for PPAz. The repulsion of the long aliphatic spacer by the Si-substrate is invoked as the main reason for the flat-on morphology observed.     

AFM and STM investigations of hydrogenated amorphous silicon: topography and barrier heights

As-grown films of hydrogenated amorphous silicon (a-Si?:?H, highly phosphorous-doped) were investigated by atomic force microscopy (AFM) and scanning tunneling microscopy (STM). Hills up to 10 nm in height and 10 to 20 nm in diameter have been observed by AFM. By using STM in a new high-sensitivity mode, (1) atomically smooth areas (roughness about 0.3 Å rms) which occur at the top of the hills, (2) subnanometer structures several Å in height which cover large parts of the surface have been identified. Simultaneous measurements of the local apparent barrier heights (LABH) show a clear correlation to the topography. Areas showing subnanometer structures have always low LABHs while the highest values of the LABH occur on the smooth areas.     

Facile measurement of polymer film thickness ranging from nanometer to micrometer scale using atomic force microscopy

As many properties of polymer thin films critically depend on their thickness, a convenient and cost‐effective method for precise measurement of film thickness in a wide range is highly desirable. Here, we present a method which enables polymer film thickness, ranging from nanometer to micrometer scale, to be facilely determined by measuring the height of an artificially created film step on smooth substrates with atomic force microscopy (AFM). Three polymeric films (polystyrene, poly(methyl methacrylate) and poly(styrene–ethylene/butylene–styrene) films), spin‐coated on either mica or quartz substrate with thickness ranging from 5.7 nm to 4.4 µm, were employed to demonstrate the procedure and feasibility of our method. The proposed method is particularly suitable for thicker polymer films, thus complementing the traditional AFM ‘tip‐scratch’ method which is generally limited to polymer films of no more than 100 nm thickness. Copyright © 2010 John Wiley & Sons, Ltd.     

Structural stability and phase transitions in WO3 thin films

Tungsten oxide (WO3) thin films have been produced by KrF excimer laser (lambda = 248 nm) ablation of bulk ceramic WO3 targets. The crystal structure, surface morphology, chemical composition, and structural stability of the WO3 thin films have been studied in detail. Characterization of freshly grown WO3 thin films has been performed using X-ray diffraction (XRD), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy (RS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) measurements. The results indicate that the freshly grown WO3 thin films are nearly stoichiometric and well crystallized as monoclinic WO3. The surface morphology of the resulting WO3 thin film has grains of approximately 60 nm in size with a root-mean-square (rms) surface roughness of 10 nm. The phase transformations in the WO3 thin films were investigated by annealing in the TEM column at 30-500 degrees C. The phase transitions in the WO3 thin films occur in sequence as the temperature is increased: monoclinic --> orthorhombic --> hexagonal. Distortion and tilting of the WO6 octahedra occurs with the phase transitions and significantly affects the electronic properties and, hence, the electrochemical device applications of WO3.     

Metalated diblock and triblock poly(ethylene oxide)-block-poly(4-vinylpyridine) copolymers: understanding of micelle and bulk structure

The paper provides new insights into the structure of Pt-containing diblock and triblock copolymers based on poly(ethylene oxide) (PEO) and poly(4-vinylpyridine) (P4VP), using a combination of atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and anomalous small-angle X-ray scattering (ASAXS). Parallel studies using methods contributing supplemental structural information allowed us to comprehensively characterize sophisticated polymer systems during metalation and to exclude possible ambiguity of the data interpretation of each of the methods. AFM and TEM make available the determination of sizes of the micelles and of the Pt-containing micelle cores, respectively, while a combination of XRD, TEM, and ASAXS reveals Pt-nanoparticle size distributions and locations along with the structural information about the polymer matrix. In addition, for the first time, ASAXS revealed the organization of Pt-nanoparticle-filled diblock and triblock copolymers in the bulk. The nanoparticle characteristics are mainly determined by the type of block copolymer system in which they are found: larger particles (2.0-3.0 nm) are formed in triblock copolymer micelles, while smaller ones (1.5-2.5 nm) are found in diblock copolymer micelles. This can be explained by facilitated intermicellar exchange in triblock copolymer systems. For both systems, Pt nanoparticles have narrow particle size distributions as a result of a strong interaction between the nanoparticle surface and the P4VP units inside the micelle cores. The pH of the medium mainly influences the particle location rather than the particle size. A structural model of Pt-nanoparticle clustering in the diblock PEO-b-P4VP and triblock P4VP-b-PEO-b-P4VP copolymers in the bulk was constructed ab initio from the ASAXS data. This model reveals that nearly spherical micellar cores of about 10 nm in diameter (filled with Pt nanoparticles) aggregate forming slightly oblate hollow bodies with an outer diameter of about 40 nm.     

旋涂水溶液前驱体制备氧化锌薄膜及其性质

通过旋涂法, 采用Zn(OAc)2·2H2O和聚环氧乙烷(PEO)的水溶液为前驱体在不同的热处理温度下制备了ZnO薄膜. PEO的加入增加了溶液的成膜性, 其较低的热分解温度有利于制得纯净的ZnO薄膜. 文中考察了在不同热处理温度下制备的ZnO薄膜的形貌、结晶性、带隙(Eg)以及电导性. 原子力显微镜(AFM)测试表明在热处理温度为400、450和500 ℃制备的ZnO薄膜的粗糙度均方根值分别为3.3、2.7和3.6 nm. 采用透射电子显微镜(TEM)测试发现ZnO薄膜中含有大量纳晶粒子. 通过测试ZnO薄膜的UV-Vis吸收光谱, 根据薄膜位于373 nm处的吸收带边计算得到ZnO的带隙为3.3 eV. 通过对薄膜的电流-电压(I-V)曲线的测试计算得到在热处理温度为400、450和500 ℃制备的ZnO薄膜的电阻率分别为3.3×109、2.7×109和6.6×109 Ω·cm. 450 ℃时制备的ZnO薄膜的电阻率最小, 主要是由于较高的热处理温度有利于提高薄膜的纯度、密度和吸附氧. 而纯度较高、密度较大的薄膜电阻率比较小; 吸附氧含量增加, 晶界势垒增大, 电阻率增大. 因此在纯度和吸附氧的双重作用下450 ℃时制备的ZnO薄膜的电阻率最小, 而500 ℃时制备的ZnO薄膜的电阻率最大.     

The electroactive multilayer films of polyelectrolytes and Prussian blue nanoparticles and their application for H2O2 sensors

Prussian blue (PB) nanoparticles were immobilized in polyelectrolyte (PE) multilayers of various compositions and thickness. Films containing nanoparticles and poly(allylamine hydrochloride) (PAH) were formed using the layer-by-layer adsorption method. A layer of branched poly(ethyleneimine) (PEI) was used to anchor the multilayer structure at the surface of a gold electrode. The films exhibited electroactive properties, increasing with the number of deposited PB layers. The properties of PEI/(PB/PAH) _n multilayers were then compared with the ones containing additionally the conductive polymer poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS). We found that the addition of the conductive, water-soluble polymer enhances the electroactive properties of the multilayer films. It also increased sensitivity of the multilayer-covered electrodes for electrochemical detection of hydrogen peroxide.     

Synthesis of thin dense titania films via an aqueous solution-gel method

Nanostructured titanium dioxide films have been reported to be used in many applications ranging from optics and solar energy devices to gas sensors. This work describes the synthesis of nanocrystalline titania films via an aqueous solution-gel method. The thin films are deposited by spin coating an aqueous citratoperoxo-Ti(IV)-precursor solution onto a silicon substrate. The influence of processing parameters like Ti⁴⁺ concentration and crystallization temperature on the phase formation, crystallite size and surface morphology of the films is studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Furthermore, the effect of successive layer deposition on the film thickness of the resulting films is studied by means of cross sectional SEM. SEM and TEM micrographs clearly show that, after optimization of the process parameters, thin, smooth, dense nanocrystalline films are synthesized in a reproducible manner. The films are composed of 15–20 nm grains. At higher crystallization temperatures (600, 650°C) also larger particles (40–70 nm) are present. XRD data reveal that a phase pure anatase film is formed at 450°C. Crystallization temperatures equal to or higher than 600 °C however give rise to the formation of both the anatase and rutile crystalline phases. The smoothness of the films is proved by their very low rms surface roughness (≤1.1 nm) measured by AFM.     

Needlelike and spherical polyelectrolyte complex nanoparticles of poly(l-lysine) and copolymers of maleic acid

We report on the bulk and surface properties of dispersions consisting of nonstoichiometric polyelectrolyte complex (PEC) nanoparticles. PEC nanoparticles were prepared by mixing poly(l-lysine) (PLL) or poly(diallyldimethylammonium chloride) (PDADMAC) with poly(maleic acid-co-alpha-methylstyrene) (PMA-MS) or poly(maleic acid-co-propylene) (PMA-P). The monomolar mixing ratio was n-/n+ = 0.6, and the concentration ranged from 1 to 6 mmol/L. Subsequent centrifugation enabled the separation of the excess polycation, resulting in a stable coacervate phase further used in the experiments. The bulk phase parameters turbidity and hydrodynamic radius (R(h)) of the PEC nanoparticles showed a linear dependence on the total polymer content independently of the mixed polyelectrolytes. This can be interpreted by the increased collision probability of the polyelectrolyte chains when the overlap concentration is approached or exceeded. Different morphologies of the cationic PEC nanoparticles, which were solution-cast onto Si supports, were obtained by atomic force microscopy (AFM). The combinations of PLL/PMA-MS and PDADMAC/PMA-MS revealed more or less hemispherical particle shapes, whereas that of PLL/PMA-P revealed an elongated needlelike particle shape. Circular dichroism and attenuated total reflection Fourier transform infrared (ATR-FTIR) measurements proved the alpha-helical conformation for the PEC PLL/PMA-P and the random coil conformation for the PEC PLL/PMA-MS. We conclude that stiff alpha-helical PLL induces anisotropic elongated PEC nanoparticles, whereas randomly coiled PLL forms isotropic spherical PEC nanoparticles.     

Control of cell adhesion by mechanical reinforcement of soft polyelectrolyte films with nanoparticles

Chemical cross-linking is the standard approach to tune the mechanical properties of polymer coatings for cell culture applications. Here we show that the elastic modulus of highly swollen polyelectrolyte films composed of poly(L-lysine) (PLL) and hyaluronic acid (HA) can be changed by more than 1 order of magnitude by addition of gold nanoparticles (AuNPs) in a one-step procedure. This hydrogel-nanoparticle architecture has great potential as a platform for advanced cell engineering application, for example remote release of drugs. As a first step toward utilization of such films for biomedical applications we identify the most favorable polymer/nanoparticle composition for optimized cell adhesion on the films. Using atomic force microscopy (AFM) we determine the following surface parameters that are relevant for cell adhesion, i.e., stiffness, roughness, and protein interactions. Optimized cell adhesion is observed for films with an elastic modulus of about 1 MPa and a surface roughness on the order of 30 nm. The analysis further shows that AuNPs are not incorporated in the HA/PLL bulk but form clusters on the film surface. Combined studies of the elastic modulus and surface topography indicate a cluster percolation threshold at a critical surface coverage above which the film stiffness drastically increases. In this context we also discuss changes in film thickness, material density and swelling ratio due to nanoparticle treatment.