Linear Diamides Derivative-Nucleated Biodegradable Poly(ethylene succinate) Polyester: Crystallization Kinetics and Aggregated Structure Manipulated by Hydrogen Bond Interaction

A linear diamides derivative (TMC300) as a nucleating agent (NA) was incorporated into biodegradable poly(ethylene succinate) (PES) to investigate effect of TMC300 on nucleation, crystallizability, crystallization kinetics, aggregated structure of PES. TMC300 enhanced significantly crystallizability and crystallization temperature of PES in cooling process at a rate of 10 ℃/min from molten state, indicating that TMC300 exhibits an excellent nucleation effect on PES. IR measurement suggested that TMC300 interacts with amorphous carbonyl and ester segment, and crystalline CH2 segment of PES via hydrogen bond. Change rate of carbonyl group is comparable to that of C‒C backbone of PES, regardless of the presence or absence of TMC300. Small difference of diffraction peak in WAXD measurement between neat PES and PES/TMC300 is probably attributed to spherulitic orientation on film surface of neat PES, and different spatial arrangements in the same crystal lattice. TMC300 enhanced carbon residue yield of PES/TMC300 composite, probably related to slight flame retardance effect.


Introduction
Polyester material has attracted more and more interests from scientists, engineers and environmentalists due to its good mechanical properties, biodegradation and biocompatibility (or low toxicity), and is considered as a promising biomaterial to replace traditional petroleum-based plastic without biodegradability. It has been widely applied in the medical material, disposable container, food packaging and agricultural film [1][2][3][4][5][6][7][8].
Poly(ethylene succinate) (PES) is a typical linear aliphatic polyester with the biodegradation and its monomer of succinic acid comes from natural resources [9,10]. It was reported that the PES exhibits comparable mechanical properties to the traditional petroleum-based plastics, such as the polyethylene and polypropylene [9][10][11][12][13][14][15][16] and increasing attention has been paid on the PES. The crystallization behavior, crystallization kinetics and aggregated structure (containing the crystalline structure) significantly influence the physical properties (material density, transparency, mechanical properties and processability), which will further affect the performances (biodegradation, gas barrier, etc.) of the polymeric material. Therefore, the crystallization kinetics and aggregated structure play an important role on the final performance of the polymeric product. The in-depth exploration of the crystallization kinetics and aggregated structure is of scientific importance to tailor the physical properties and performances of the polymeric material. The PES shows the extremely low crystallizability and no discernible crystallization peak can be found in its cooling process (as presented in Fig. 1), resulting in long processing cycle and high time cost in the processing.
The nucleating agent (NA) as a kind of common additive has been widely applied in the scientific research and material processing due to economy, time saving, efficiency, convenience and eco-friendliness. With loading of the heterogenous NA, the polymer molecular chains frequently nucleate on the surface of the NA at a higher temperature and with low free energy, and the crystal growth can be triggered immediately, thus both the crystallization temperature and crystallization rate enhance for the polymeric material.
In the presence of the NA, many polymeric materials exhibit the improved physical properties and tailored performances. To date, many NAs have been incorporated into the PES to manipulate the crystallization/melting behavior, crystal morphology, microstructure and enzymatic hydrolysis rate, enhance thermal stability and improve mechanical properties of the PES [17][18][19][20][21][22][23][24][25][26][27]. For example, Clarke A and Qiu et al. used the cellulose nanocrystals (CNC) as the NA to the PES, to enhance the nucleation effect of the PES and improve the crystallizability of the PES significantly [28,29]. In addition, in our previous researches, the TMC306 and EBH also exhibited a good nucleation effect on the PES. Obvious enhancements in the melt-crystallization temperature (T c ) of the PES was found for the PES/0.5%TMC306 and PES/0.5%EBH, compared to neat PES [30,31]. Among the NAs aforementioned, some inorganic NAs show the agglomeration morphology and weak interfacial strength/ interaction with the PES, resulting in the uncontrolled crystal shape, undesirable or relatively poor physical properties and performances of the composite. By contrast, the organic NA should be a better candidate to increase the interfacial interaction and to achieve the uniform dispersion of the NA in the PES matrix.
It was reported that several multiple amides-based derivatives as the excellent NAs present outstanding nucleation effect via the hydrogen bond interaction. These NAs not only modulate the polymorphism, tailor mechanical properties, increase the T c , crystallization rate, degree of crystallinity (X c ), thermal stability and gas barrier performance, but also induce the crystals to self-assemble into the shish-kebablike (or cone/needle-like) structures in the isotactic polypropylene (iPP) [32][33][34], poly(L-lactide) (PLLA) [35][36][37][38][39][40][41][42][43][44][45] and poly(1,4-butylene adipate) (PBA) [3,[46][47][48]. Generally, an excellent NA presents a higher T c and melting temperature (T m ) than the polymer matrix because the solidified NA crystal can act as the heterogeneous NA on which the molten polymer molecular chains nucleate, before the onset of the crystallization of the polymer [39]. It was documented that the linear multiple amides-based NA with the amide group flanked with the benzene terminal groups, shows a better effect on the nucleation and mechanical properties of the PLLA [45].
Recently, a linear organic derivative (octamethylenedicarboxylic dibenzoylhydrazide (abbreviated as TMC300), see its chemical structure in Scheme 1) bearing the amide groups which are directly linked with the benzene terminal groups, was reported to enhance substantially the T c and crystallization rate of the bacterially synthesized copolyester, poly(3hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) [4]. In this work, the TMC300 bearing the multiple amides as a NA was incorporated into the PES to investigate the effect of the TMC300 on the crystallization kinetics and aggregated structure of the PES. It is anticipated that via the hydrogen bond interaction between the PES and amide group of the TMC300, the crystallizability can be enhanced and crystallization process can be accelerated for the PES. In addition, by means of the in-situ Fourier transform infrared (FTIR) spectroscopy, the time-dependent aggregated structure of the TMC300-nucleated PES was monitored in the crystallization process, which enables us to follow the evolution of aggregated structure and elucidate the crystallization mechanism of the PES in depth at a molecular level.

Materials
The PES (M w = 10,000 Da) was purchased from the Sigma-Aldrich Co., Ltd. (Shanghai, China) and used as received without further purification. The TMC300 was synthesized in our group, and the synthesis method and procedures refer to the literature [4]. Prior to use, the TMC300 was milled as particles with a size lower than 20 μm.

Preparation of the PES/TMC300
The TMC300 was added into the PES-containing chloroform solution and well stirred. After evaporation of the chloroform, the composite sample was transferred into the vacuum oven at 40 ℃ for 5 h to remove completely the chloroform. The dried sample was marked as PES/x%TMC300, where x represents the weight fraction of the TMC300 (f TMC300 ) in the composite.

Characterization and Measurement
Differential scanning calorimetry (DSC). The crystallization and melting curves were recorded on a DSC instrument (PE 4000, USA). For the non-isothermal crystallization, the sample (5-8 mg) was heated to 190 ℃ and held for 3 min to remove the thermal history, then cooled to -20 ℃ at various rates (2, 5, 10 and 20 ℃/min). Followed by being reheated to 190 ℃. For the isothermal crystallization, the molten sample at 190 ℃ was cooled quickly (with a rate 100 ℃/min) to different T c s (60, 65, 70 and 75℃) to complete the crystallization process. After the isothermal crystallization, the sample was also reheated to 190 ℃. The DSC data (including the crystallization enthalpy, cold crystallization enthalpy, recrystallization enthalpy and melting enthalpy) were calculated using the unit mass (g) of the sample (J/g).
Polarized optical microscopy (POM). The crystal morphology observation was performed using a POM (XPF550C, Caikon Co. Ltd., Shanghai, China). The sample between 2 glass slides was heated to 190 ℃ to remove the thermal history, and pressed slightly to form a thin film with about 0.05 mm. Eventually, the molten film sample was transferred to a hotstage on which the desirable T c was set for the isothermal crystallization.
Fourier transform infrared (FTIR) spectroscopy. The FTIR spectrum was collected on an IR instrument (TEN-SOR 37, Bruker, Germany). The accumulation and resolution are 16 scans and 1 cm −1 , respectively. First, the sample placed between 2 KBr discs was heated to 190 ℃ to remove the thermal history, and pressed slightly to form a thin film with about 0.05 mm. Then the sample was transferred to a hotstage preset to the T c = 25 ℃ to complete its isothermal crystallization. For the time-dependent in-situ IR measurement, a higher T c (75 ℃) was set because it allows us to observe the IR spectral alteration real time during a long time period. The molten film sample at 190 ℃ was transferred rapidly to a hotstage preset to 75 ℃ for a slow isothermal crystallization, and each IR spectrum was collected with a time interval of 2 min.
Scanning electron microscopy-energy dispersive spectrometer (SEM-EDS). The N element mapping of the TMC300 in the PES matrix was recorded with a SEM-EDS instrument (SU3500, Hitachi, Japan). The image of the cross section of broken sample was obtained with an acceleration voltage of 30 kV and a working distance of 10-400 mm.
Wide angle X-ray diffraction (WAXD). The crystal structure of the sample was measured on a WAXD instrument (Rigaku Corp., Tokyo, Japan) with Ni-filtered CuKα radiation (λ = 0.154 nm), worked at 40 kV and 200 mA. The sample sandwiched between 2 iron plates was heated to 190 ℃ and held for 3 min to erase the thermal history. Then the molten sample was pressed slightly to form a film with 1 mm and transferred to a hotstage preset to 25 ℃ to complete the isothermal crystallization.
Thermogravimetric analysis (TGA). Thermal stability of the sample was investigated using a TGA instrument (SDT Q600, TA, USA). The sample was heated from the room temperature to 600 ℃ with a rate of 10 ℃/min in the presence of the N 2 . Thermogravimetric analysis/infrared spectrometry (TG-IR) measurement was performed on the TGA instrument, which is coupled with a Fourier transform infrared spectroscope.

Non-isothermal Crystallization
The non-isothermal crystallization and subsequent heating curves are presented in Fig. 1. No discernible crystallization peak can be found for neat PES and the T c of neat TMC300 is about 100 ℃, as shown in Fig. 1a. Upon incorporation of the TMC300, a sharp crystallization peak appeared for the PES with 0.3%TMC300, indicating the TMC300 as an effective NA enhanced significantly the crystallizability. With a further increase in the f TMC300 (0.5% and 1%), the T c of the PES changed little, probably ascribed with the saturated effect of the TMC300 NA [4]. In the subsequent heating curve, neat PES showed a sharp cold crystallization (cc) peak at T cc , a recrystallization (rc) peak at T rc , and two melting peaks at T m1 and T m2 , respectively, as presented in Fig. 1b. The cold crystallization peak is an indicative of the rearrangement or adjustment of neat PES molecular chains in the heating process, that is, the insufficient crystallization occurred or the degree of the crystallinity is low for neat PES in the former cooling process. With the loading of the TMC300, no cold crystallization peak can be found, revealing that the TMC300 increased the orderness of the alignment of molecular chains to a certain extent in the cooling process. Multiple melting behaviors of the PES should be attributed to the melting-recrystallization-remelting mechanism, which is widely reported in the polymeric material. The TMC300 exhibited a T m at about 160 ℃, substantially higher than that of the PES. By contrast, the nucleation effect of the TMC300 is better than that in our previous results [30,31].
The parameters of the thermal property measured using the DSC are summarized in Table 1, where ∆H c , ∆H cc , ∆H rc and X c represent the crystallization enthalpy in the cooling process, cold crystallization enthalpy, recrystallization enthalpy in subsequent heating process and relative degree of the crystallinity, respectively. The X c value refers to the ratio of ∆H m ʼ and ∆H m 0 ((∆H m ʼ /∆H m 0 ) × 100%), and ∆H m ʼ = (∆H m + ∆H cc + ∆H rc ) and ∆H m 0 is ∆H m of an infinitely large crystal of the PES. It was documented that the ∆H m 0 value of the PES is 180 J/g [15]. The X c value of the PES enhanced markedly in the presence of the TMC300, but a slight increase in the X c value can be found for three PES/ TMC300 composites (with the f TMC300 = 0.3-1%), confirming again that the nucleation of the PES tends to saturation with the higher f TMC300 . To the best of our knowledge, the ∆H m 0 value of the TMC300 is unavailable. The non-isothermal DSC curves at various rates are presented in Fig. S1 (Supplementary Material). With an increase in the cooling rate, the T c of the PES decreased, suggesting that the lower cooling rate is favorable for the nucleation and crystallization of the PES. No crystallization peak could be found for neat PES when the cooling rate is 10 or 20 ℃/min, indicating that the difficulty in the crystallization for neat PES. The DSC data in the cooling process from the molten state at the rates of 2, 5 and 20 ℃/ min, respectively, are shown in Table S1 (Supplementary Material). On the whole, both the T c and the absolute value of the ∆H c of the PES increased slightly with the f TMC300 , at the same cooling rate.
Besides, the nucleation activity of the TMC-300 with different loadings, were also studied based on the Dobreva model [21,49,50], and the results are shown in the Supplementary Material (Fig. S2). Fig. S2 presents (a) the lnβ plots as a function of 1/(ΔT p ) 2 and (b) the nucleation activity of TMC-300 with different loadings. As presented in Fig. S2b, The value of the nucleation activity gradually decreased with the loading of TMC300, and when 1%TMC300 was added, the value of the nucleation activity was the lowest.
It confirms that 1%TMC300 has the best nucleation effect on the PES, which is consistent with the results in Fig. 1a.
To the best of our knowledge, the TMC300 in this work shows better nucleation effect than other NAs that have been reported.

Isothermal Crystallization and Crystallization Kinetics
Isothermal crystallization curves of neat PES and PES/ TMC300 at different T c s (60, 65, 70 and 75 ℃), are shown in Fig. 2. No obvious crystallization peak is discernible for neat PES. However, with addition of the TMC300, the sharp crystallization peak of the PES appeared and it narrowed much with an increase in the f TMC300 . In addition, the crystallization time decreased largely in the presence of the TMC300, reflecting that the TMC300 is indeed an excellent NA on the PES.
For quantitative analysis of the crystallization kinetics of neat PES and PES/TMC300 at different T c s, modified method and guideline based on Avrami Equation were  [51][52][53][54]. Figure 3 shows the X t as a function of the crystallization time (t), in which the X t represents the relative degree of the crystallinity at the time t. All these plots present the "S" shapes. Obviously, at the same t, the PES exhibited much higher crystallinity in the presence of the TMC300, and the TMC300 shortened substantially the crystallization time at which 100% crystallinity is achieved. The Avrami plots are shown in Fig. 4, and good linear fitting with correlation coefficient higher than 0.991 was obtained in each plot and their slopes are close to each other. The  Table 2. t 1/2 is the crystalliztion hafe-time at which the relative degree of the crystalinity is 50%. n is the Avrami exoponent ralated to both the nucleation manner (homogeneous or heterogeneous, n 1 ) and crystal growth dimension (n 2 ). n = n 1 + n 2 and n 1 equals to 1 in the case of homogeneous nucleation or 0 in the case of heterogeneous nucleation. k is the crystallization rate constant which is influenced by both the nucleation and crystal growth. Clearly, the t 1/2 depressed significantly and k increased substantially with the loading of the TMC300, indicating that the crystallization rate of the PES enhanced largely in the presence of the TMC300. In terms of n, neat PES is close to 3 (instead of 4), seemingly suggest that neat PES exhibits 2-dimensional crystal (n 1 = 1 and n 2 = 2). However, from the POM image in Fig. 5a, neat PES showed the typical 3-dimensinal spherulites not 2-dimensional crystal. It probably is ascribed with some impurities in the PES. With an increase in the f TMC300 , n declined gradually to 2, suggesting that the morphology transition from the 3D spherulite in neat PES to 2D shape in the PES/TMC300. Due to some uncertainties, calculated n value is not an integer.

Crystal Morphology Observation
65 ℃ as an example was chosen a T c to observe the crystal morphology. Neat PES presented a large spherulite at 65 ℃ (Fig. 5a) and, the crystal size decreased markedly and crystal density increased significantly with the loading of the TMC300, especially in the PES/1%TMC300 (Fig. 5d). It indicates that the TMC300 showed the outstanding nucleation effect on the PES. Figure 6 shows the IR spectra (panels a and c) of neat PES, TMC300 and PES/TMC300 at T c = 25 ℃ in two wavenumber regions. For clear distinguishing of subtle difference, the corresponding 2nd derivatives of the IR spectra are also presented in Fig. 6 (panels b and d). Neat PES showed the IR absorption peaks at 1730 and 1774 cm −1 , attributed to the carbonyl (C = O) group in the crystalline (denote as "C = O cry." in Fig. 6a) and amorphous (denote as "C = O amo." in Fig. 6a) phase [55][56][57], respectively. No IR peak could be found for neat TMC300 in the region of 1800-1700 cm −1 .

Hydrogen Bond Interaction Measured by IR
With incorporation of the TMC300, the peak at 1774 cm −1 shifted to 1770 cm −1 (as presented in Fig. 6b) and that at 1730 cm −1 changed little, suggesting that the TMC300 (-NH-or -CH 2group) interacts with the C = O group of the amorphous phase of the PES. An IR peak at 1605 cm −1 is assigned to the amide (O = C-NH-) group [58] of the TMC300 and it moved to a lower wavenumber region (1601 cm −1 ), indicating that the amide group of the TMC300 interacts with the PES (-CH 2 -/-CH 3group). The IR peak at 1116 cm −1 is associated with the ester (O = C-O-C) group of the PES and it moved gradually to 1122 cm −1 with an increase in the f TMC300 , as shown in Fig. 6c and d, reflecting that the hydrogen bond interaction also exists between the ester of the PES and TMC300.

Possible Nucleation Mechanism
The nucleation mechanism of the polymer in the presence of the NA can mainly be attributed to the chemical nucleation  and epitaxial nucleation [59,60]. Chemical nucleation can be described as follows. In the sample preparation process, the chemical reaction between the polymer and NA occurs and newly formed substance can act as the NA of the polymer. In this case, there is an extremely low possibility that chemical reaction between the PES and TMC300 occurred. Epitaxial nucleation refers to good matching of the crystal lattice between the polymer and NA. To the best of our knowledge, no data on the crystal lattice sizes of the TMC300 is available at present. It is difficult that to confirm that whether or not there is good crystal lattice matching between the PES and TMC300. It was documented that the uniform dispersion of the multiple wall carbon nanotube (MWNT) enhances greatly the nucleation and crystallizability of the poly(ɛ-caprolactone) (PCL) and the superfine MWNT NA exhibits the supernucleation effect on the PCL [61]. Authors speculates that the homogeneously/evenly distribution of the MWNT is an important factor leading to the nucleation of the PCL. In this work, the hydrogen bond interaction between the PES and TMC300 is favorable for good dispersion of the TMC300 in the PES matrix, which induced the nucleation of the PES.

Time-Dependent In-Situ FTIR
For in-situ observation of spectra change, time-dependent FTIR spectra of neat PES and PES/1%TMC300 collected at 75 ℃, are shown in Fig. 7. From Fig. 7a, the intensity of most of IR peaks (at 1734, 1450, 1415, 1379, 1349, 1314,   1046, 971, 924 and 872 cm −1 ) increased with the crystallization time and these peaks are considered as the crystalline peaks (denoted as the ↑ arrow). The intensity of an IR peak at 1146 cm −1 decreased with the crystallization time and it is an amorphous peak (denoted as the ↓ arrow). With loading of the TMC300, two new IR absorption peaks between 1620 and 1550 cm −1 appeared, related to the amide group of the TMC300. These two peaks are the crystalline one because they enhanced in their peak intensities. In addition, the peak shift occurred for 3 peaks in the presence of the TMC300, that is, 1415 cm −1 1422 cm −1 , 1146 cm −1 1152 cm −1 and 1046 cm −1 1040 cm −1 , respectively. The intensity variation and peak shift should be ascribed with the reorganization/ adjustment of the molecular chains of the PES in the crystallization process. Based on the previous literatures on the polyester [62][63][64][65], the IR peaks assignment of the PES is summarized as follows. The peak at 1734 cm −1 is assigned to the carbonyl stretching mode, and those in 1500-1400 and 1400-1300 cm −1 are ascribed with the CH 2 bending and wagging mode, respectively. Peaks in the wavenumber of 1300-1100 cm −1 are attributed to the ester stretching mode. Those in 1100-1000 cm −1 are related to C-C backbone stretching mode. IR peaks in 1000-800 cm −1 are assigned to CH 2 rocking mode. It should be mentioned that the positions of the carbonyl and ester group in Fig. 7 differ from those in Fig. 6, probably resulted from the variation in the T c .
With combination of IR results from Figs. 6 and 7, the hydrogen bond interaction formed between the PES and TMC300 is illustrated in Fig. 8. The TMC300 interacted For direct comparison of the crystallization rate, the normalized intensity of several IR characteristic peaks (assigned to the carbonyl, ester and C-C group, respectively) as the crystallization time, are plotted, as shown in Fig. 9. The peak intensity of the carbonyl and ester group increased with the time, but that of the ester group depressed. Clearly, by contrast, the intensity change of these 3 IR peaks accelerated substantially with loading of the TMC300, revealing that the TMC300 enhanced highly the crystallization rate of the PES.
The variation rate of the carbonyl group was comparable to that of the C-C backbone, regardless of the presence or absence of the TMC300.

Crystal Structure Measurement by WAXD
The WAXD patterns of neat PES, TMC300 and PES/ TMC300 at T c = 25 ℃ are presented in Fig. 10. Neat PES showed two main peaks assigned to the diffraction planes (021) and (200) [14]. With loading of the TMC300, a weak should peak assigned to the diffraction planes (121) of the PES [20] could be found. Absence of this should peak in neat PES is probably attributed to its significantly large crystal (as presented in Fig. 5a), resulted in the orientation of neat PES spherulite on the film surface. Similar results have been reported in poly[(3-hydroxybutyrate)-co-(3-hydroxyhexanoate)] [66], poly(3-hydroxybutyrate) [67] and poly(ethylene adipate) [68]. It is noteworthy that there was an obvious difference in the peak intensity ratio between (021) and (200), that is, I(021)/I(200), for neat PES and PES/TMC300, probably ascribed with different spatial arrangements in the same crystal lattice [69][70][71]. Hence, the TMC300 had little effect on the crystal structure of the PES.

Thermal Stability by TGA
The mass and derivative mass as a function of the temperature are shown in Fig. 11a and b. The mass loss of the sample occurred mainly in the temperature range of 300-455 ℃. From Fig. 11a (TGA curves), both neat PES and PES/ TMC300 presented one-step decomposition behavior, but neat TMC300 showed two-step decomposition one, which could be clearly seen in the DTG curves in Fig. 11b (peaks 1 and 2). From 300 to 370 ℃, the order of the thermal degradation temperature is: neat PES > PES/TMC300 > neat TMC300. From 425 to 455 ℃, the thermal degradation temperature of neat TMC300 is higher than those of neat PES and PES/TMC300. In addition, the residue yield of neat PES is lower than those of neat TMC300 and PES/TMC300 at 600 ℃. The mass loss of neat TMC300 in the first stage (peak 1) is probably attributed to the evaporation of formed NH 3 and H 2 O gases in a lower temperature region, and that in the second stage (peak 2) should be associated with the escape of the gases related to the decomposition of the benzene ring and C-C backbone in a relatively higher temperature region. The decomposition of neat PES and PES/ TMC300 are mainly ascribed with the developed H 2 O, CO and CO 2 , and other low molecular weight gases containing  and PES/TMC300 are probably related to the slight flame retardance effect of the TMC300. It was reported that many organic substances with the N or P element (as the excellent flame retardant) increased the flame retardance or fire resistance of the polymeric composites, because these flame retardants migrate to the surface of the polymeric material and react with the polymer to form a thin carbon layer (with a lower heat conductivity) to prevent from the direct contact with the heat flow [72,73].
The IR spectra of (a) PES and (b) PES/1%TMC300 with increasing the temperature, are shown in Fig. 12. In the pyrolysis process, the CO 2 and other volatile gas product containing the C-H, C = O, C-O, respectively, could be found. By contrast, below 420 ℃, the intensity of IR absorption peaks in Fig. 12b (PES/1%TMC300) are higher than corresponding those in Fig. 12a (neat PES), indicating that the TMC300 facilitates the thermal degradation of the PES, that is, the pyrolysis of the PES/1%TMC300 occurs earlier than neat PES, in good agreement with the results in Fig. 11.

Conclusions
No discernible crystallization peak could be found for neat PES, but the PES/TMC300 showed a sharp crystallization peak, suggesting that the TMC300 increased highly the crystallizability of the PES. In our The TMC300 enhanced substantially the crystallization rate and shortened significantly the crystallization time of the PES, indicating that the TMC300 is a good nucleating agent of the PES. IR investigation revealed that the hydrogen bond exists between the TMC300 and the amorphous carbonyl and ester group, and crystalline CH 2 group of the PES. Absence of the weak (121) diffraction peak of neat PES is probably attributed to the spherulitic orientation on neat PES film surface. The difference of I(021)/I(200) between neat PES and PES/TMC300 should be ascribed with different spatial arrangements in the same crystal lattice.