Article pubs.acs.org/Macromolecules
New Aspects for the Hierarchical Cooperative Motions in Photoalignment Process of Liquid Crystalline Block Copolymer Films Masami Sano,† Mitsuo Hara,† Shusaku Nagano,*,‡ Yuya Shinohara,⊥ Yoshiyuki Amemiya,⊥ and Takahiro Seki*,† †
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan ‡ Nagoya University Venture Business Laboratory, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan ⊥ Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa 227-8561, Japan S Supporting Information *
ABSTRACT: The realignment process of azobenzene-containing liquid crystalline (LC) block copolymer films by irradiation with linearly polarized light (LPL) was investigated in detail by time-resolved grazing incidence X-ray scattering measurements using a synchrotron beam. By using a newly synthesized diblock copolymer possessing a poly(hexyl methacrylate (PHMA) block with a lowered glass transition temperature (Tg = −5 °C), intense X-ray scattering signals were obtained, which favorably provided precise and detailed time course profiles and information on the interplay between the hierarchical structures involved along the realignment process. The LC layers were softened and fluctuated at an early stage by LPL irradiation which induced shrinkage of the cylinder to cylinder distance of microphase separation patterns before the alignment change. Interestingly, the ordering process of the MPS cylinder array of larger hierarchical structure proceeded faster than that of the azobenzene LC layer of smaller feature size in the realigned state. Decisive evidence was obtained to support the subdomain rotation mechanism in the realignment process.
1. INTRODUCTION The dynamic self-assembly and motions of molecular systems containing different size features are ubiquitous in biological systems, and mimicking such hierarchical systems with synthetic organic polymer materials has always been a fascinating challenge in materials chemistry.1,2 Block copolymers that form microphase separation (MPS) structures by selfassembly have been attracted much attention for versatile fabrications of mesoscopic structures.3−11 How to control the MPS orientation is of great concern in light of future applications such as ultrafine resolution lithography processes.12−17 Block copolymers possessing a liquid crystalline (LC) block are a class of alluring materials that possess hierarchical structures composed of oriented LC units and MPS domains with sufficient dynamic properties.18−22 Recently, the photoalignment of LC polymers23−33 has been applied to azobenzene- (Az-) containing block copolymer systems, and the MPS structures have been successfully aligned by irradiation with linearly polarized light (LPL).25,28,29,34−41 A particular feature in the photoresponsive processes is that they can be readily “realigned” repeatedly by subsequent LPL irradiation of different direction of the electric vector (E).34 Our recent approach by grazing incidence angle X-ray scattering (GI-SAXS) measurements using a synchrotron beam revealed that the realignment of the hierarchical structures © XXXX American Chemical Society
consisting of the MPS cylinders and smectic LC matrix proceed in a highly collective and cooperative manner.42,43 In the former work, a diblock copolymer, poly(butyl methacrylate) (PBMA) (glass transition temperature (Tg) = 20 °C) connected with an Az-containing LC polymer was employed (PBMA-b-PAz, Scheme 1a). The procedures for the LPL induced realignment is schematically shown in Scheme 1b. It has been revealed that the realignment proceeds via three stages including the induction period, collective alignment change, and post fusion of the subdomains in the successive direction.43 Structural characterizations at the intermediate stage of the realignment process were successfully achieved by polarized optical microscopic (POM) and transmission electron microscopic (TEM) observations. From these results, the rotation mechanism of subdivided domains was suggested be plausible to explain the hierarchical alignment change.43 However, due to insufficient signal intensity of X-ray scattering from the PBMAb-PAz film, precise time-resolved GI-SAXS was not satisfactorily obtained. Herein, we report on the results of time-resolved GI-SAXS observations using a homologous diblock copolymer possessing Received: February 11, 2015 Revised: March 16, 2015
A
DOI: 10.1021/acs.macromol.5b00299 Macromolecules XXXX, XXX, XXX−XXX
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Macromolecules Scheme 1. Chemical Structure of Block Copolymers (a) and Scheme of Photoalignment and Realignment Procedures by LPL (b)
obtained by atomic force microscopy (Nanopics 2100, Seiko Instruments). The film was partly scratched by spatula and the height difference between the film surface and substrate surface was measured. The typical film thickness was approximately 200 nm. LPL irradiation at 436 nm was performed with a mercury lamp source (REX-250, Asahi Spectra) at 1 mW cm−2 with a 436 nm band-pass filter (Asahi Spectra). The light intensity was 1.0 mW cm−2. Note that the energy dose numbers correspond to the time in seconds. 2.4. Time-Resolved GI-SAXS Measurements. Time resolved GI-SAXS measurements were performed on the BL- (beamline-) 6A system at the KEK Photon factory in Tsukuba, Japan. A monochromated X-ray radiation source at the wavelength λ of 0.150 nm with the beam size of approximately 250 μm × 500 μm, and the detection was performed with an X-ray CCD pixel (PILATUS 100 and 300 K detectors, DECTRIS). The detailed procedures and analyses were described in the previous paper.42,43 The peak intensities extracted from 2D scattering images in the time-resolved GI-SAXS measurements were monitored for target in-plane peaks corresponding to the MPS periodicity and Az smectic layers observed in smaller (detector: PILATUS 300 K) and larger (detector: PILATUS 100 K) angle regions, respectively.
poly(hexyl methacrylate) (PHMA) as the amorphous polymer block (PHMA-b-PAz, Scheme 1a). Because of lowered Tg (−5 °C) of PHMA, the gained flexibility of the amorphous chain led to highly ordered MPS patterns, which then provided significantly improved intense X-ray scattering signals. By using PHMA-b-PAz, the subdomain rotation mechanism in the photorealignment process was substantiated, and the dynamic interplay between the LC phase and the MPS domain in the course of the cooperative realignment process was elucidated in more detail.
3. RESULTS AND DISCUSSION 3.1. Characterizations of PHMA-b-PAz. The average numbers of repeating units of PHMA-b-PAz synthesized in this work for PHMA and PAz were 43 and 48, respectively (Mw = 2.7 × 104 and Mw/Mn = 1.16) as estimated by GPC and 1H NMR data (Figure S1, Supporting Information). DSC measurements and POM observations revealed that the thermal phase transition property of the Az polymer block was glass−55 °C−smectic C−90 °C−smectic A−115 °C−isotropic (Figure S2, Supporting Information), and the Tg of PHMA was −5 °C. The thermophysical properties coincided well with each homopolymer, indicative of the formation of MPS structure. The phase separation structure was evaluated using a bulk sample by SAXS measurements. The scattering peaks were observed at 0.22, 0.38, 0.59, and 2.26 nm−1 (Figure S3, Supporting Information) at room temperature. Peaks in the smaller angle region (scattering vector q [4π (sin θ)/λ] = 0.22, 0.38, and 0.59 nm−1, θ and λ being scattering angle and wavelength of X-ray, respectively) were originated from the MPS patterns. These scattering peaks were observed at 1:√3: √7 ratio, indicating that a hexagonally packed cylindrical MPS array structure was formed. The cylinder to cylinder distance was estimated to be 29 nm. The peak observed in the wider angle region (q = 2.26 nm−1) gave the periodicity of 2.8 nm, which reflected a spacing of the smectic C layer of PAz (see below). SAXS measurements were also achieved at 95 °C (smectic A phase of PAz matrix) and 125 °C (isotropic phase of PAz matrix) (Figure S3, Supporting Information). The cylinder to cylinder distance of MPS structure at smectic A phase was essentially unchanged (q = 0.23 nm−1, d = 28 nm), but a significant reduction was observed above the isotropization temperature (q = 0.28 nm−1, d = 20 nm). The layer spacing became larger (q = 1.87 nm−1, d = 3.4 nm) at 95 °C. In the photoalignment and realignment processes, series of measurements were performed at 95 °C.42,43 3.2. Photoinduced Dichroic Ratio Change of PHMA-bPAz Film. PHMA-b-PAz films were prepared on quartz plates by spin-casting and annealed at 120 °C. The initial alignment was achieved by irradiating LPL at 1000 mJ cm−2 to this film at 95 °C. Successively, LPL set at 90° of the initial one was irradiated in the same manner (see Scheme 1b).
2. EXPERIMENTAL SECTION 2.1. Materials and Synthesis. Hexyl methacrylate was purchased from Tokyo Chemical Industry (TCI) Co., Ltd., and distilled before use. Other materials for polymer synthesis were described previously.42 The block copolymer of PHMA-b-PAz was synthesized by the atom transfer radical polymerization method as was described for PBMA-bPAz.42 2.2. Measurements. Number-averaged molecular weight (Mn) and polydispersity index (PDI) were estimated by gel permeation chromatography (GPC) using tetrahydrofran as eluent, using a UV detector (UV-41), an RI detector (RI-101) and pump operated at 0.3 mL min−1 (DS-4, Shodex). Molecular weights and PDI were evaluated with respect to monodisperse polystyrene standards (Tosoh). 1H NMR spectra were recorded with a GSX-270 (JEOL) spectrometer using tetramethylsilane as the standard signal. Differential scanning calorimetic (DSC) measurements were carried out using a DSC Q200 MO−DSC-UV (TA Instruments). The scanning rate was 2 °C min−1. POM observation was undertaken using a BX51-P (OLYMPUS) and a DP28 camera (OLYMPUS) with Cellscan controller software. SAXS measurements to evaluate the microphase-separated structures in the bulk state were performed with a NANO-Viewer X-ray diffractometer (Rigaku) equipped with an imaging plate (FUJIFILM) as the detector. CuKα radiation (λ = 0.154 nm) was used as the X-ray beam source. The diameters of the X-ray beams were 0.3−0.6 mm which were collimated by pinhole slits. The camera length was 960 mm. Polarized UV−visible absorption spectra of the thin films were taken on an Agilent 8453 spectrometer equipped with a polarizer in front of the sample. 2.3. Photoalignment Procedures. Thin films of the synthesized diblock copolymers were prepared on quartz plates by spin-casting (2000 rpm) from a 2% by weight chloroform (TCI Co. Ltd.) solution. The film was first annealed at 130 °C (isotropic state of PAz) on a thermostated stage before photoalignment, and then the initial alignment was performed by irradiating with LPL at 95 °C (smectic A state of PAz). Film thickness was evaluated by surface profiles B
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Macromolecules Figure 1 shows the polarized UV−visible absorption spectra of the initial (a) and successively aligned film (b). As shown, a
Figure 2. 2D GI-SAXS images in the small angle region for the PHMA-b-PAz film (200 nm thickness) aligned for the initially photoalignmed state (a and b), and successively realigned state to the orthogonal direction (c and d) by irradiation with LPL at 1000 mJ cm−2. Incident directions for the measurements are shown as beam I and beam II in schemes on the right.
Figure 1. Polarized UV−visible spectroscopic data for a PHMA-b-PAz film (200 nm thickness) aligned using the procedures shown in Scheme 1b. Sets of data correspond to spectra after the initial LPL irradiation at 1000 mJ cm−2 (a) and after the realignment LPL irradiation at 1000 mJ cm−2 in the orthogonal direction (b). The symbols ∥ and ⊥ in the spectra denote the direction parallel and perpendicular to E of the realignment (subsequent) LPL. Changes in the in-plane DR as a function of the exposure energy are indicated in part c.
in the projected plane. These scattering spots unequivocally indicates that the packing of the MPS cylinder were aligned as a 2D hexagonal array as displayed in the scheme of Figure 2. In contrast, no scattering was observed with beam II (b). The anisotropy of the scattering indicates the monoaxially aligned state of the cylinders directing perpendicular to the E of LPL irradiation. In the realigned state (c and d), on the other hand, the scattering from the cylinder array appeared when the X-ray incidence was set parallel to the realigned LPL E (b, beam II). Thus, the MPS cylinders were realigned perpendicular to the polarized field of the successive LPL irradiation (realigned LPL). It should be noted here that, for the previous PBMA-bPAz films, only the two in-plane spots at the horizontal position were observed without the spots in the 30° direction (see Figure 2 in ref 42) In this way, the PHMA-b-PAz films with the lowered Tg coil block provided highly ordered hexagonal packing with clearer interfaces of the phase transition. The significantly increased X-ray scattering intensity is the key to obtain unveiled information on the dynamic realignment behavior of the hierarchical structures as will be mentioned below. The slight deviation in qy value for the MPS cylindrical structure between bulk (qy = 0.22 nm−1, d = 29 nm) and film (qy = 0.20 nm−1, d = 32 nm) can be ascribed to a distortion of the hexagonally packed cylinders by a confinement in the thin film state. 3.4. Time-Resolved GI-SAXS Measurements for the MPS Array. We recently suggested that the photoreorientation of the MPS cylinder structure of PBMA-b-PAz involved the rotation of the submicrometer sized LC domain with retained smectic LC and MPS cylinder phases.43 At the intermediate stage (DR = 0), static structures have been captured by GISAXS measurements, POM and TEM observations. However, direct time-course measurements of the alignment changes by GI-SAXS for the MPS array structure were not achievable due to insufficient scattering signal intensities for PBMA-b-PAz. In this previous work,43 the time-course GI-SAXS measurement
strong dichroic nature appeared. Here, a dichroic ratio (DR) was used to evaluate the degree of orientation, which is defined as (A⊥ − A∥)/(A⊥ + A), where A⊥ and A∥ denote the absorbance taken with the probing beam set perpendicular and parallel to the second E of LPL for the realignment. The initial and the realigned DR were −0.52 (a) and 0.50 (b), respectively. The inversion in sign indicates the realignment to the perpendicular direction, and the essential coincidence of the absolute values shows that the realignment was fully performed in these procedures. By using polarized UV−visible absorption spectroscopy, we monitored time-course changes of in-plane DR. In Figure 1c, the change in DR is plotted against light exposure of the successive LPL for the realignment. Upon irradiation with the LPL in the orthogonal direction, the DR value of −0.52 suddenly started to increase after an induction period of 150 mJ cm−2, and reached almost to a constant value of 0.50 after 400 mJ cm−2. The inversion of the sign was observed around 280 mJ cm−2. This nonlinear cooperative behavior was similar as observed for the previous PBMA-b-PAz system.43 3.3. GI-SAXS Measurements. The orientation of MPS cylinder structures in the films was evaluated by GI-SAXS measurements. The incident directions of X-ray beam in the GI-SAXS experiments are denoted as beam I and beam II as schematically indicated in Figure 2. 2D GI-SAXS images of the initial state and the realigned state were shown in parts a−d. When the incidence direction of the X-ray beam was set perpendicular to the LPL E direction (a, beam I), the scattering peaks corresponding to the MPS cylinder array were observed (a), Scattering spots in the in-plane direction (qy) was observed at 0.20 nm−1 (d = 32 nm) and additional clear spots were observed at (2/√3)qy in 30° direction from the horizontal line C
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azimuthal angles between E of LPL and the X-ray incidence beam. 2D GI-SAXS images originated from the MPS cylinder array together with 1D profiles in the in-plane direction at selected time shots are displayed in Figure 3 for 0° (a), 45° (b), and 90° (c) azimuthal incidences. Movies showing the dynamic changes of the scattering signals are attached in Supporting Information (Movie S1 − S3). Figure 4 displays the time course changes of the scattering intensity at different azimuthal incidence angles (a−d) together with the change in DR (e). The features of the changes observed at each incident angle are summarized as follows. In-Plane Angle 0° (Movie S1, Figure 3a, and Figures 4a and 4b). The most characteristic changes were observed in this azimuthal angle. Strong scattering from the cylinder array was observed at the initial state. The scattering intensity decayed upon the orthogonal LPL irradiation for the realignment, however the process was not simple. Interestingly, as clearly seen in Movie S1, the scattering obviously showed a sudden shifted from qy = 0.20 nm−1 (d = 32 nm) to a wider range of 0.26 nm−1 (d = 24 nm) at an early stage at ca. 50 mJ cm−2. Snapshots at 0, 50, 280, and 400 mJ cm−2 are shown in Figure 3a. The similar shrinkage of the MPS structure was also observed in thermal phase transition from smectic A for 0.22 nm−1 to isotropic phase for 0.28 nm−1 in bulk SAXS measurement (Figure S4, Supporting Information). The shrinkage should be ascribed to the increased chain mobility of the Az LC segments. In the smectic A state, the side chains are aligned side-by-side, and the main chain is extended with
has been achieved only for the LC layer, and the analyses were made in an assumption that the motions of the MPS and the LC layer are exactly synchronized.42 By using PHMA-b-PAz in the present work, precise time-resolved approaches for both the two different hierarchical structures became possible for the first time. Scheme 2 schematically shows the setup of the timeScheme 2. Schematic Illustrations of the Experimental Setup of Time-Resolved GI-SAXS Measurements: Side View (a) and Top View (b)
resolved GI-SAXS measurements in the side (a) and top views (b). In the top view scheme (b), 0°, 45°, and 90° denote the
Figure 3. Snapshots of time-resolved 2D GI-SAXS images in the small angle region for the PHMA-b-Pz film (200 nm thickness) in the course of LPL-induced alignment change of MPS cylinders. X-ray incident directions were 0° (a), 45° (b), and 90° (c) as indicated in Scheme 2b. Energy doses of the realignment LPL are shown in each image. D
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Figure 5. Time course profiles in GI-SAXS scattering intensity changes at the peaks in the wider angle region at qy = 1.87 nm−1 (d = 3.4 nm, detecting a periodicity of smectic LC laye) for the PHMA-b-PAz film as a function of the exposure energy of the realignment LPL (a−c). Profiles a, b, and d were obtained with incidence X-ray beam at 0°, 45°, and 90°. Changes in the in-plane DR with the exposure energy are indicated in part d.
Figure 4. Time-course profiles in GI-SAXS scattering intensity changes at the peaks in the small angle region (detecting a periodicity of MPS cylinder array) for the PHMA-b-PAz film as a function of the exposure energy of the realignment LPL (a−d). Profiles a and b were taken at 0° incidence, corresponding to peaks at qy = 0.20 nm−1 (d = 32 nm) (a) and 0.26 nm−1 (d = 24 nm), respectively. Profiles c and d were obtained with incidence X-ray beam at 45° and 90°, respectively. Changes in the in-plane DR with the exposure energy are indicated in part e.
150 mJ cm−2) and sharply increased until ca. 300 mJ cm−2, followed by a gradual increase until 600 mJ cm−2. It is noteworthy that the GI-SAXS scattering peaks were observed in all X-ray incidence directions of 0°, 45°, and 90°, and particularly the scattering peak intensity with 45° incidence showed the maximum at the intermediate point where DR = 0. These facts indicate that the mesoscopic MPS cylinder arrays were retained, which unequivocally indicates that the realignment of the MPS cylinder array proceeds via the subdomain rotation mechanism.43 3.5. Time-Resolved GI-SAXS Measurements for the LC Layer. Changes in the scattering intensity due to the smectic A LC layer structure in the wider scattering regions were also monitored at qy = 1.87 nm−1 (d = 3.4 nm) simultaneously. The motion pictures are attached in Supporting Information (Movies S4−S6). Time course scattering changes are indicated in Figure 5a−c together with the profile of DR change (part d). The enhancing and decaying of the scattering peaks were observed in the opposite directions for those of MPS cylinder array mentioned above. The features of the scattering changes are briefly summarized as follows. In-Plane Angle 0° (Movie S4 and Figure 5a). The scattering intensity was enhanced monotonously after approximately 150 mJ cm−2. The profile feature was seemingly same as that for the MPS array at 90° incidence shown in Figure 4d. In-Plane Angle 45° (Movie S5 and Figure 5b). The intensity profile showed a maximum at 280 mJ cm−2, exactly at the same position at DR = 0 (d). This behavior was similar as observed for the MPS array with 45° incidence (Figure 4c). In-Plane Angle 90° (Movie S6 and Figure 5c). The initial scattering intensity quickly decreased before 50 mJ cm−2 as similarly observed for the MPS array observed with 0° azimuthal incidence (Figure 4a). 3.6. On the Hierarchical Alignment Changes of PHMA-b-PAz. In the previous system of PBMA-b-PAz, we concluded that the motions of MPS cylinder array and the LC smectic layer are fully synchronized. However, in the present PHMA-b-PAz system, considerable deviations in the reorienting motions between the two different hierarchical structures were admitted. Figure 6 represents the comparisons of normalized scattering peak intensity with time for the decay
nearly all-trans-zigzag conformations.44 By involvement of bentstructured cis-Az isomers upon 436 nm LPL irradiation, more gauche conformations will be involved in the main chain. Thereby, the cylinder to cylinder distance becomes smaller than that before irradiation. This phenomenon seems to be related with photoinduced mechanical deformations in the microscopic28,45 and macroscopic46,47 scales exhibiting the material contractions along with the photoisomerization to the cis-Az. This peak shift was observed only in the 0° X-ray incidence direction in Scheme 2b, and no shift was admitted in other azimuthal in-plane directions (45° and 90°). The time course profiles in Figure 4a confirms that the initial scattering intensity for d = 32 nm suddenly decreased before 50 mJ cm−2, followed by a gradual decrease until 300 mJ cm−2. On the other hand, the transient peak for d = 24 nm appeared from 40 mJ cm−2 (Figure 4b). The transient peak intensity also decreased gradually until 300 mJ cm−2. In-Plane Angle 45° (Movie S2, Figure 3b, and Figures 4c). Snapshots of the time-resolved 2D scattering data with 45° incidence direction are shown in Figure 3b for 0, 50, 280, and 600 mJ cm−2 irradiation. Initially, no scattering peak was recognized (0 mJ cm−2). After LPL irradiation for realignment was performed, scattering peaks appeared at qy = 0.24 nm−1 (d = 26 nm) at 50 and 280 mJ cm−2. With longer irradiation at 600 mJ cm−2, the scattering peak disappeared again. Therefore, the scattering peaks only appeared at the intermediate stage. The scattering intensity gave a maximum at 265 mJ cm−2, which almost corresponded to the intermediate point at DR = 0 (cf. Figure 4, parts c and e). Beyond this point, the intensity gradually decreased until 600 mJ cm−2. In-Plane Angle 90° (Movie S3, Figure 3c, and Figures 4d). Figure 5c indicates the snapshots of the 2D scattering at 0, 150, 280, and 600 mJ cm−2. In this incidence direction, the increase of the scattering due to the cylinders started to appear at 150 s, and the scattering intensity was increased and saturated above 600 mJ cm−2. With this X-ray incidence, the peaks were observed from 120 mJ cm−2 at qy = 0.21 nm−1 (see Figure 3c, E
DOI: 10.1021/acs.macromol.5b00299 Macromolecules XXXX, XXX, XXX−XXX
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same in the UV−visible spectroscopic and GI-SAXS measurements for both PBMA-b-PAz43 and PHMA-b-PAz systems. Therefore, time course changes can be compared directly. The overall realignment process became prolonged for the present PHMA-b-PAz system; the induction period and the intermediate point at DR = 0 were elongated as 50 → 150 mJ cm−2 and 80 → 280 mJ cm−2, respectively. Probably, this delayed change is due to formation of more ordered hierarchical structure realized in the PHMA-b-PAz system, which will resist the photoinduced perturbation and alternations. Relating to the above aspect, the overall feature of time course profiles was also changed. In the previous PBMA-b-PAz case, in-plane X-ray scattering signals in the orthogonal direction starts to appear after the DR inversion is ceased. For the present PHMA-b-PAz system, such signals (corresponding to the curves in Figure 4d and Figure 5a) were enhanced along with the DR change. This different feature seems to arise from the delayed alignment change of the Az mesogens. The time constant observed in the orthogonal enhancing direction shown in Figure 4d and Figure 5a almost agree with that observed for PBMA-b-PAz with an induction period of 150 mJ cm−2 (Figure 8b in ref 43). In the above manners, the substitution of the coil polymer block makes significant changes in the properties of dynamic motions. Systematic explorations to elucidate the effect of coil polymer block should deserve further investigation. Work in this regard is in progress.
Figure 6. Comparisons of normalized time-course profiles in GI-SAXS scattering intensity changes observed in the smaller (for MPS cylinder array) and wider (for smectic layer) angle regions in the peak decaying (a) and enhancement (b) processes. Open and closed circles correspond to data for the MPS cylinder array and smectic LC layer, respectively.
(a) and enhancement (b) processes of cylinder (open circle) and LC (close circle) structures. In the peak decaying process, the X-ray intensity scattered from the smectic layer structure was reduced more rapidly than that from the MPS cylinder array structure (a). This behavior is plausible because the photoresponsive LC matrix becomes initially disordered, and this successively leads to a disordering of the light-inert and larger PHMA cylinder hexagonal array. In contrast, the peak enhancement in the opposite direction progressed unexpectedly in the opposite way, i.e., the MPS cylinder array became ordered faster than the smectic LC layer matrix of the smaller feature size (b). We assume that the softness of the PHMA domain with low Tg contributes to the faster ordering of the MPS cylinder array. The X-ray data in Figure S4 show that the regular MPS structure exists even in the isotropic state of the PAz domain at 125 °C. This means that the structure formation of the MPS is not directly coupled with the molecular order of the LC layer matrix. It seems that the realigned MPS is readily directed and ordered due to the soft nature following the orientation preference of the Az LC matrix, but the ordering of the Az LC layer matrix itself requires longer time to complete the ordering. This work revealed that a significant shrinkage of the cylinder distance from 32 to 24 nm occurred at the earlier stage (
