SUPPLEMENTARY INFORMATION

Transcription

1 SUPPLEMENTARY INFORMATION Visualization of the Self Assembly of Silica Nanochannels reveals growth mechanism Christophe Jung, Peter Schwaderer, Mark Dethlefsen, Ralf Köhn, Jens Michaelis * and Christoph Bräuchle * Figures S1 to S10 Figure S1: Histogram of the AFM height data Figure S1. Histogram of the height data from the AFM data shown in Figure 1b. The corresponding Gaussian fits are plotted using coloured lines. The insert shows a magnification of a region of the histogram. nature nanotechnology 1

2 supplementary information Figure S2: Overlay AFM / Fluorescence images. The diffusional and orientational behaviours of the TDI dye molecules in the channels of the hexagonal silica layers were previously investigated at the single molecule level. 1,2 The molecules show linear movement, with their transition dipole moment aligned along their trajectories, reflecting well-ordered structural areas of the host. Hence, these regions imaged by the TDI dye molecules correspond to highly structured domains of parallel channels in which the fluorophores are remarkably aligned along the direction of the pores. The absolute direction of the channel system in the hexagonal domains can thus be directly determined from the analysis of the polarization-modulated fluorescence patterns of TDI. Figure S2b shows a polarization modulated confocal image of domains in which TDI was incorporated at ensemble concentration (C= 10-7 mol/l in the synthesis solution of the mesoporous film substrate). The domains are imaged by the fluorescence signal of TDI. The striped fluorescence patterns indicate that TDI is highly polarized over the whole domain areas. The insert to the right is a magnification of the region highlighted in yellow. A phase shift of the stripes from the left to the right part of the insert reveal a change of the overall direction of the channel system. The in-plane overall orientations of the pores were computed using regions of interest of pixels in size (corresponding to an area of 0.75 µm 0.75 µm). The orientations corresponding to the regions of interest highlighted with the green (1) and red squares (2) were determined from the graphs shown in the left and the right panel of Figure S2c, respectively (see Methods for details about the procedure of determination of the angles). In each plot, the sum of the pixels for each horizontal line is displayed as a function of the pixel number along the vertical for the reference curve (gray squares) 2 nature nanotechnology

3 supplementary information as well as for the fluorescence signal (green and red squares). The fit of these curves according to Eq. 1 and 2 are overlaid as full lines (see Methods). The phase difference between reference and signal corresponds to the absolute orientation of the transition dipole moments of the TDI molecules (the horizontal serves as 0 for the determination of the angles). The calculated angle for the regions A and B are 92 ± 4 and 59 ± 5, respectively. The orientations of the TDI molecules i.e. of the channels reveal thus the presence of a boundary region in which the pores change their direction. Hence, polarization modulated confocal microscopy allows obtaining a precise map of the porous architecture of the hexagonal silica layers. Figure S2. Polarization modulated confocal microscopy. (a) Experimental setup. (b) Polarization modulated fluorescence image of several hexagonal domains. The insert is a magnification of the region highlighted with a yellow rectangle. The striped fluorescence patterns reveal the strong polarization of the TDI guest molecules which are aligned along the pores in the hexagonal layers. The nature nanotechnology 3

4 supplementary information arrows indicate the orientations of the channels in the regions marked with the green (1) and red (2) squares. (c) Determination of the orientations in the regions 1 and 2. The angles are extracted from the phase difference between the fluorescence signal (coloured curves) and the reference (gray curves). See text for details. Figure S3: Stability over time. The demonstration that the hexagonal domains are surrounded by a rigid silica matrix and not only consist of CTAB molecules is based on the comparison of different properties between the hexagonal domains and a hexagonal ordered phase of pure CTAB. The layer structures and stability over time were compared. As the phasediagram of CTAB forbids a hexagonal structure at the solid-air interface a hexagonal phase of pure CTAB is predicted to be mestastable. 3 Hence, the observation of a significant difference in the aging behavior of the hexagonal domains and the hexagonal phase of pure CTAB can provide valuable indications about the presence of a silica framework in the hexagonal domains. A hexagonal phase of pure CTAB was prepared by spin-coating an aqueous solution containing CTAB, ethanol and TDI molecules (C= 10-7 mol/l) on a glass cover-slip (see Methods for details) which was subsequently exposed to ethanol vapor for 1 h. This procedure results in the formation of hexagonal layers which were then investigated by polarization modulated confocal and AFM microscopy. The polarization modulated confocal image shown in Figure S3a exhibits striped fluorescence patterns nearly over the whole field of view. This is a clear indication for the presence of a hexagonal structure as described in Figure 2 and Figure S2. This was 4 nature nanotechnology

5 supplementary information confirmed by investigating the diffusion of single TDI guest molecules which exhibit nearly linear trajectories in these structures, as will be shown in Figure S4b. Tappingmode AFM images (data not shown) revealed that the hexagonal phase of pure CTAB has a thickness of nm. Additionally, small steps with a height of nm were observed, indicating a layer structure. This value is slightly smaller than for the hexagonal silica structure (3.0 ± 0.4 nm) as expected for pure hexagonal CTAB. This constitutes a first hint that silica is present in the hexagonal domains. In order to compare the aging behavior of the two systems samples were investigated (i) directly after preparation and (ii) three months later. Figure S3A and S3B shows polarization modulated confocal images of a hexagonal phase of pure CTAB directly after its preparation and three months later, respectively. Whereas a polarized fluorescence is observed in Figure S3a, only small dots of a weak fluorescence are visible in Figure S3b indicating the disappearance of the hexagonal phase. This effect was observed repeatedly over the whole sample surface. This confirms that the hexagonal ordered phase of pure CTAB is not stable over time. In contrast, hexagonal domains were observed over the whole sample surface immediately after their formation as well as three months later (Figure S3c and S3d). They exhibit in both cases a strong, polarized fluorescence. We conclude that the stabilization of the hexagonal structure is due to the presence of a polymerized silica matrix in the hexagonal domains. nature nanotechnology 5

6 supplementary information Figure S3. Time stability of the hexagonal phase of pure CTAB and of the hexagonal domains. (a - b) Polarization modulated confocal images of hexagonal phase of pure CTAB and of hexagonal domains directly after their formation. In both cases the strong polarization of the TDI molecules indicated by the striped fluorescence patterns reveals the presence of a hexagonal structure. (c d) The same samples imaged three months later. Whereas the hexagonal phase of pure CTAB degraded, the hexagonal domains are still well structured, as indicated by the strong polarization of the TDI guest molecules. 6 nature nanotechnology

7 supplementary information Figure S4: Single Molecule diffusion The investigation of the diffusion of single guest molecules supplies valuable information about the mesoporous host structure (e.g. the presence of defects within the mesoporous structure) as well as about the dynamics taking place. The diffusional behavior of single TDI dye molecules incorporated as guests in the hexagonal silica layers as well as in the surfactant micelles of pure hexagonal CTAB were investigated and compared. The presence of a silica matrix in the hexagonal domains is expected to change the host/guest interactions and, as a consequence, to have an influence on the diffusional behavior of TDI compared to hexagonal phase of pure CTAB. The two sample systems were prepared with ultra low TDI concentration to ensure single molecule observation (C= mol/l in the synthesis solutions, see methods for details). The samples were exposed to a chloroform saturated atmosphere during the measurement to ensure mobility of the TDI molecules, as described elsewhere 2. The trajectory of a single TDI molecule moving inside the channels of a hexagonal domain is displayed in Figure S4a. The guest molecule undergoes back and forth movements and is confined between the two extremities of the linear trajectory 2. This reveals the presence of defects within the structure where the pores are closed (dead ends). The trajectories in the hexagonal phase of pure CTAB are at first sight very similar (three examples are shown in Figure S4b). However, slight differences can be observed by closer inspection of the trajectories. First, the TDI molecules can move over longer distances in the cylindrical micelles of pure CTAB (up to 10 µm, compared to typically 1 µm in the hexagonal domains). This suggests that dead ends are much less frequent or even absent in the hexagonal phase of pure CTAB. This can be explained by the presence of a polymerized silica matrix in the hexagonal domains nature nanotechnology 7

8 supplementary information which may obstruct the pores at some locations. Second, the trajectories are not perfectly linear in the hexagonal phase of pure CTAB but may exhibit curves, as observed for the two left trajectories of Figure S4b. This is in contrast to the extremely linear trajectories commonly observed with the hexagonal domains and may result from the much higher flexibility of the pure CTAB cylindrical micelles in the absence of a silica matrix. The diffusion behavior of the single TDI guest molecules was quantified based on a Mean Square Displacement (MSD) analysis. The diffusion coefficient for each TDI molecule was extracted as described previously 2. The histograms of the diffusion coefficients in the hexagonal domains and in the hexagonal phase of pure CTAB are plotted in Figure S4c as green and red bars, respectively (about 50 trajectories were analyzed for each system). The distributions were fitted with Gaussian functions, overlaid as full lines in Figure S4c. Both distributions are relatively broad, revealing the presence of strong heterogeneities. Importantly, they are well separated with average diffusion coefficients of 2500 nm 2 /s for the hexagonal domains and nm 2 /s for the hexagonal phase of pure CTAB. The significant difference in the mobility of TDI can be explained by strong interactions between TDI and the silica walls of the hexagonal domains (e.g. between the oxygen atoms of TDI and silanol groups) which decrease the apparent diffusion coefficient. Hence, this constitutes a strong argument in the favor of the presence of a rigid silica matrix within the hexagonal domains. 8 nature nanotechnology

9 supplementary information Figure S4. Single molecule diffusion in the hexagonal domains and in the hexagonal phase of pure CTAB. (a) Trajectory of a single TDI molecule diffusing in a hexagonal domain. The trajectory is extremely linear with a length of about 1µm. (b) Trajectories of three TDI molecules moving in a hexagonal phase of pure CTAB. (c) Histogram of the diffusion coefficients of single TDI molecules diffusing in hexagonal domains (green bars) and in the hexagonal phase of pure CTAB (red bars). The diffusion is about eight times faster in the hexagonal phase of pure CTAB than in the hexagonal domains. To summarize Figure S3 and S4 we demonstrated that the hexagonal domains contain a rigid silica matrix based on the following observations: (i) The layer to layer distance in the hexagonal domains is slightly higher than in the hexagonal phase of pure CTAB (3.0 ± 0.4 nm compared to 2.6 ± 0.2 nm, respectively). (ii) The hexagonal domains are extremely stable over time, which is not the case for the hexagonal phase of pure CTAB. The presence of a rigid silica matrix in hexagonal domains can explain the increased stability. nature nanotechnology 9

10 supplementary information (iii) The single TDI molecule trajectories are shorter in the hexagonal domains compared to the hexagonal phase of pure CTAB, suggesting the presence of numerous dead ends in the hexagonal domains where the pores are obstructed with polymerized silica. Moreover, the trajectories are not perfectly linear in the hexagonal phase of pure CTAB but can exhibit curves, which may result from the much higher flexibility of the pure CTAB cylindrical micelles in the absence of a silica matrix (iv) The average diffusion coefficient is about eight times lower in the hexagonal domains compared to the hexagonal phase of pure CTAB. This can be explained by strong interactions between TDI and the silica walls of the hexagonal domains. Figure S5: Lamellar structures - growth and formation of multi-layers The formation and growth dynamics of the unpolarized structures described in Figure 2 were investigated by polarization modulated confocal microscopy by incorporating TDI dye molecules at ensemble concentration (C= 10-7 mol/l in the synthesis solution of the mesoporous film substrate), and acquiring sequences of fluorescence images at T= 35 C and RH= 50%. Figure S5a-d displays four frames extracted from the region highlighted with a white square in Movie S2 at t= 23, 173, 200 and 254 min, respectively. Strong dynamics of formation and disappearance of unpolarized structures can be observed in the movie. In particular, discrete levels of fluorescence intensities can be observed for TDI growing or decreasing in size cooperatively in the unpolarized structures, revealing the presence of a multi-layer structure for the unpolarized structures. 10 nature nanotechnology

11 supplementary information Figure S5a-d is analyzed by plotting the histograms of the fluorescence intensity for each pixel as red, black, green, and blue thin lines, respectively (Figure S5e). Prior to the analysis all fluorescence images were processed with a Gaussian-blur filter (5 by 5 pixels) in order to obtain smoother curves. The histogram corresponding to Figure S5a (t= 23min) could be fitted with a bi-gaussian curve (red thick line). The first peak corresponds to fluorescence signal arising from the TDI molecules diffusing inside and on the surface of the mesoporous film substrate. For better comparison the position of the first peak was arbitrarily set to zero in each histogram. The second peak (at position 44) arises from the fluorescence signal of the two unpolarized structures visible in Figure S5a. 150 min later (Figure S5b) the unpolarized structures have grown in size and, importantly, they are about three times brighter, as can be calculated from the position (126) of the second peak of the corresponding histogram (black thick line in Figure S5e). This can be explained by the appearance of new layers between t= 21 min and t= 173 min which allow the incorporation of additional TDI molecules, resulting in a stronger fluorescence intensity. Assuming that the growth starts with the formation of a monolayer (as observed in Figure S5a), the three times stronger fluorescence signal observed in Figure S5b would correspond to unpolarized structures with three layers of a CTAB phase. This hypothesis is confirmed by the analysis of Figure S5c (t= 200 min) and S5D (t= 254 min). In both cases one can observe how the fluorescence intensity decreases stepwise from the periphery to the center of the unpolarized structures, however with different fluorescence intensities for the two figures. The corresponding histograms could be fitted with tri-gaussian functions, displayed as green thick line for Figure S5c and blue thick line for Figure S5d. In both cases a peak at the position of about 81 is nature nanotechnology 11

12 supplementary information found, which would correspond to two layers of a CTAB phase. Additionally, a third peak is found in each case at the position expected for a tri-layer in Figure S5c and for a monolayer in Figure S5d. Hence, from t= 173 min until the end of Movie 3 the CTAB layers of the two unpolarized structures degrade cooperatively passing stepwise from three layers to two layers and from the bilayer to a single monolayer. In summary, these data demonstrate that the unpolarized structures are multi-layers of a CTAB phase. Figure S5. Lamellar structures: formation and growth of multi-layers of CTAB. (a d). Polarization modulated confocal images of two unpolarized structures extracted from the region 12 nature nanotechnology

13 supplementary information marked with a white rectangle in Movie S2 at t= 21, 173, 200 and 254 min, respectively (the slight fluctuations within the structures are a background effect arising from the apparatus and are not due to the polarization of the TDI molecules). The cooperative stepwise formation and growth of CTAB multilayers can be observed. (e) Histograms of the fluorescence intensities from Figure S5a-d displayed as red, black, green and blue thin lines, respectively. The histogram could be fitted with multi-gaussian functions overlaid as thick lines. In each case, the first peak corresponds to the TDI molecules diffusing inside and on the surface of the mesoporous film substrate (set to zero), whereas the peaks of higher fluorescence intensity arising from the unpolarized structures reveal the presence of multilayers of CTAB molecules. Figure S6: Diffusion of single TDI molecules within the lamellar structures. The single molecule investigation of the unpolarized structures can reveal information which is not accessible to ensemble measurements (such as those presented in Figure 2, Movies S1 and S2) since a study on an individual molecular basis allows resolving sub-populations of diffusing molecular species. Unpolarized structures such as described in Figure 4 were grown on a mesoporous film substrate with ultra-low TDI concentration (C= mol/l in the synthesis solution of the mesoporous film substrate) to ensure individual observation of the guest molecules. The temperature was set to T= 50 C and the relative humidity to RH= 50% during the measurements to allow enough mobility for the TDI molecules, and wide-field movies were acquired with an integration time of 15 ms. Three populations of diffusing TDI molecules can be readily distinguished in Movie S3: (i) Fast molecules confined in circular region of about 20 µm in diameter in the center of the view field, (ii) much slower molecules moving outside the confinement region, and (iii) nearly immobile molecules distributed over the entire field of view. The nature nanotechnology 13

14 supplementary information molecules of the three populations exhibit random diffusion. Interestingly, exchange event between the first and the second populations can occasionally be observed at the boundaries of the confinement region. Figure S6a shows the overlay of 1000 widefield images: during their walks the molecules of the first population image the confinement region which appears as a blurred fluorescence signal (red arrow), the molecules of the second population exhibit blurred tracks (green arrow) and the quasiimmobile TDI molecules of the third population show a quasi-gaussian shaped pattern due to their very low mobility (blue arrow). 42 molecules of the three populations together were tracked and their trajectories are displayed in Figure S6b as red (population 1), green (population 2) and blue (population 3) tracks. The global size of the tracks becomes smaller from population 1 to 3, as already observed in Movie S4. The mean square displacements were plotted versus time in Figure S6c as colored full lines. For each population the mean MSD is displayed as thick colored line. The presence of three distinct diffusivities is confirmed by the clear separation of the three MSD bundles. The diffusion coefficients of the single TDI molecules of each population were calculated from the MSD plots assuming a two-dimensional Brownian diffusion according to the Einstein-Smoluchowski relation: MSD = 4 Dt Eq. 3 where D and t are diffusion coefficient and time, respectively. The mean diffusion coefficients for each population are D 1 = nm 2 /s, D 2 = nm 2 /s and D 3 = nm 2 /s for populations 1, 2 and 3, respectively. The shape and the size of the confinement region combined with the fact that the diffusion is random allow us to attribute population 1 to molecules diffusing in the unpolarized structures observed in the polarization modulated confocal measurements. 14 nature nanotechnology

15 supplementary information Furthermore, the analysis of other single molecule experiments (data not shown) allowed us to attribute populations 2 and 3 to molecules diffusing on the surface of the mesoporous film substrate and inside its channels, respectively. Note here that the thickness of the mesoporous film substrate (~120 nm) is much smaller than the z- resolution of the wide-field setup (2-3 µm), which allows observing the three populations simultaneously. In summary, the diffusivity of the single TDI molecules in the unpolarized structures is much higher than on the film substrate surface (~50 times higher diffusion coefficient) as well as in the hexagonal pores of the mesoporous film substrate (~300 times higher diffusion coefficient). Moreover, the diffusion in the unpolarized structures is totally random in contrast to the diffusion within hexagonal silica layers. 2 These observations were expected for diffusion of guest molecules in two dimensional lamellas. Moreover, the diffusion of single TDI molecules in a lamellar phase of pure CTAB was very similar than the one in the unpolarized structures i.e. random diffusion with a mobility of the molecules in the same order of magnitude (MSD plots shown as black lines in Figure 5c). The determined mean diffusion coefficient within pure CTAB ( nm 2 /s), however, was about four times higher than in the unpolarized structures. This can be explained by the absence of interactions with silica, similarly to what was observed for the hexagonal phase of pure CTAB (see Figure S4). Hence, we conclude that the unpolarized structures are lamellar phases. nature nanotechnology 15

16 supplementary information Figure S6. Diffusion of single TDI molecules in a lamellar structure. (a) Overlay of 1000 wide-field fluorescence images (integration time of 15 ms per frame). The lamellar structure appears as a blurred disk in the center (population 1, red arrow), the TDI molecules moving on the surface of the mesoporous film substrate as blurred tracks (population 2, green arrow) and the TDI molecules moving slowly inside the mesoporous film substrate as nearly Gaussian-shaped fluorescence pattern (population 3, blue arrow). (b) Trajectories of single molecules from the three populations (identified by red, green and blue tracks, respectively). (c) Mean-square displacement as a function of time. The diffusion is distinct for the three populations. 16 nature nanotechnology

17 supplementary information Figure S7: Growth kinetics. Important insights about the formation mechanism and the growth kinetics can be gained by recording sequences of topographic AFM images before and during the formation of the mesoporous layers. After spin-coating of the mesoporous film substrate and storage for one week at a temperature T= 20 C and constant Relative Humidity RH= 40%, the sample is placed on an AFM microscope at T= 30 C and RH= 60%. This procedure initiates self- assembly of the silica nanochannels on top of the mesoporous film substrate. Figure S7a-e shows a series of topographical images extracted from a movie (Movie S5 in Supplementary Materiel) at times t= 0, 71, 89, 91 and 150 min, respectively. At t= 0 min the surface of the mesoporous film substrate appears empty, as can be seen in Figure S7a. After 71 min (see Figure S7b), 13 small nucleation islands appear almost simultaneously which are barely visible in the topographic image. We attribute this to an intermediate lamellar phase, as will be explained later. A later time-point of the movie (t= 89 min, Figure S7c) reveals an interesting transition phenomenon. During the first part of the scan (above the red arrow in Figure S7c) the measured topography of all the observed islands is roughly 3 nm. Since the lamellar phase is extremely soft (as observed by AFM indentation measurements, data not shown) the observed topography is not a good measure of the actual height. Suddenly (event indicated by the red arrows), islands appear with a well-defined height of 6.3 ± 0.2 nm. Thus, we directly observe the fast phase transition of the metastable lamellar structures to hexagonal bilayers. This is followed by tangential growth of the islands with a constant thickness (Figure S7-e). nature nanotechnology 17

18 supplementary information The growth kinetics for the single hexagonal bilayers i.e. after their formation at t= 89 min were analysed by plotting the growth rate R(t) defined as: 1 da( t) R( t) = Eq. 4 C( t) dt where C(t) is the circumference and A(t) is the area of a domain as a function of time t. The formula reflects the fact that the growth of the area of the hexagonal bilayers is brought about by the incorporation of further building molecules along the circumference of the step edge. In the graph displayed in Figure S7f each scatter colour corresponds to a different hexagonal domain. The rates are almost constant, but exhibit at discrete time points single peaks (coloured dots in brackets). These peaks are caused by events where two hexagonal domains merge. The growth rate for all mesoporous bilayers together is plotted versus time as a black thick line. It is a constant function of time with an average value of 0.19 ± 0.07 µm/s, giving the characteristic growth rate under the applied experimental conditions. The growth stops once the reactive species are used up (about 140 min, data not shown) Hence, the applied methodology allows the quantitative characterization of the growth of such mesoporous structures. 18 nature nanotechnology

19 supplementary information Figure S7. Growth kinetics. (a-e) Sequence of AFM images showing the formation of hexagonal bilayers. Images were recorded at scan speeds of 1s/line. The inserts in b, c and d are magnifications of the regions marked with white rectangles in the corresponding images. (f) Growth rate R(t) for the individual hexagonal bilayers visible in a-e (coloured scatters) as well as for all the bilayers together (black thick line). The growth rate is nearly constant during the expansion of the mesoporous layers. Figure S8: Flattening of the AFM images - Line-by-Line algorithm Raw AFM images often contain significant noise and errors in the height signal due to the sequential nature of the scanning mechanism, piezo non-linearities and temperature dependent drift. These result in a convolution of the topographical image with a curved background (Figure S8a). The resulting topography probability distribution (Figure S8b) reflects how these effects distort the expected bimodal distribution of a flat background with plateaus of uniform height. nature nanotechnology 19

20 supplementary information Routinely in AFM scanning a line-by-line filtering algorithm is applied to extract height data from the measured raw data. Typically, such algorithms approximate the surface curvature by a polynomial fit and adjust neighboring lines for minimal distance after deconvolution. These standard methods work well, if only a small area is occupied by structures compared to the overall imaging area. In the case of the domains observed here, this is not always the case. We therefore developed an optimized line-by-line method for flat surfaces and plateaus. In the first step the domain borders are determined using a Sobel edge detection algorithm. The information about the edge positions is utilized to calculate a background mask. To this end, for each line of the scan data points directly on the edges are omitted and the data values on both sides of the resulting gaps are smoothly joined by shifting one side of the data by a constant value to align the average height of 10 data points on both sides. The resulting background (Figure S8c) is then filtered using a standard line-by-line algorithm. Figure S8d (upper panel) shows the comparison between the fitting of the raw data (shown in blue) with this custom algorithm (red line) to that with a regular line-by-line algorithm (green line). The red line fits much better the background s curvature. The lower panel (Figure S8d) displays the corrected data obtained with the two algorithms. While the regular algorithm (green line) fails in deconvoluting the plateau topography from the curved background, the custom algorithm (red line) improves background recognition resulting in a very flat plateau structure. As an example of such a filtered image, the raw data from Figure S8A is shown after deconvolution in Figure S8e. The corresponding topography probability distribution 20 nature nanotechnology

21 supplementary information (Figure S8f) features two well separated peaks which distinguish the background from the domain. Figure S8. Flattening of the AFM images - Line-by-Line algorithm (a) Raw AFM height data. (b) Extracted probability distribution of the heights. The distribution features several peaks, but does not allow to distinguish between plateaus and background. (c) Background mask calculated by the custom line-by-line fitting algorithm. (d) Comparison of the custom and regular algorithms. The upper panel nature nanotechnology 21

22 supplementary information displays the data from one a scan line across a single plateau (blue line), the fit utilizing a regular linefitting algorithm (green line) as well as the fit with the customized routine (red line). The lower graph displays the deconvoluted height data of the line-scan calculated by the respective fits. While the regular algorithm only compensates the linear tilt of the data, the custom routine successfully decouples the bending of the background curvature from the plateau. (e) Computed height image after custom filtering. (f) Calculated distribution of heights in (e), featuring a clear separation between background and the plateau. Figure S9: Degradation of the hexagonal domains at RH= 80% Figure S9. Degradation of the hexagonal domains at RH= 80%. Polarization modulated fluorescence image of hexagonal domains. After their formation the hexagonal domains partially dissolve or lose their hexagonal structure under action of too high water concentration. 22 nature nanotechnology

23 supplementary information Figure S10: Transmission Electron Micrograph of a spin-coated mesoporous film. Figure S10: Transmission electron microscopy (TEM) image of a CTAB-templated hexagonal mesoporous film show small domains (as the ones highlighted with the white ellipses), whose sizes never exceed nm. Methods: For the preparation of the mesoporous films, 80 ml of the mesoporous film substrate solution (prepared as described previously) were spin-coated on Si3N4 membranes 30nm in thickness supported by a small silicon wafer with a 500 mm 500 mm window (PLANO; Wetzlar). The TEM images of the mesoporous films were obtained with a JEOL 2011 transmission electron microscope operating at 200 kv. nature nanotechnology 23

24 supplementary information Movie S1 to S5 Movie S1: Fluorescence movie: domain growth and lamellar to hexagonal phase transitions. Scale bar: 10µm. Movie S2: Lamellar structures: formation and growth of multi-layers of CTAB. Scale bar: 10µm. Movie S3: SMS within the lamellar structures. Scale bar: 10µm. Movie S4: Encapsulation of single TDI molecules during growth of the hexagonal layers. Scale bar: 2 µm. The red arrow indicates the growth direction of the domain structure. In this case the channels are perpendicular to the growth direction, as indicated by the linear trajectories of the single TDI molecules encapsulated within the growing domain. Movie S5: Growth kinetics (AFM). Scale bar: 2µm. References Jung, C., Hellriegel, C., Michaelis, J., & Bräuchle, C., Single-molecule traffic in mesoporous materials: Translational, orientational, and spectral dynamics. Adv. Mater. 19 (7), (2007). Jung, C. et al., Diffusion of oriented single molecules with switchable mobility in networks of long unidimensional nanochannels. J. Am. Chem. Soc. 130 (5), (2008). Fontell, K.K., A.; Lindström, B.; Maciejewska, D. Ngern, S. Puang, Pase Equilibria and structures in ternary systems of a cationic surfactant CTAB or (C16TA)2SO4, alcohol, and water. Colloid Polym. Sci. 269 (7), (1991). 24 nature nanotechnology