Conformational properties of rigid and semiflexible cyclic chains are still unclear owing to few experimental researches on dilute solution properties. Five cyclic amylose tris(3,5dimethylphenylcarbamate) (cADMPC) samples ranging in the weight-average degree of polymerization from 23 to 150 were prepared from enzymatically synthesized cyclic amylose. Light scattering and small-angle X-ray scattering measurements were made on the samples to determine the weight-average molar mass Mw, the particle scattering function P(q), and the zaverage mean-square radius of gyration S 2 z in methyl acetate (MEA), 4-methyl-2-pentanone (MIBK), and tetrahydrofuran (THF) at 25 C. The obtained P(q) and S 2 z data were analyzed on the basis of the cyclic wormlike chain model to determine the wormlike chain parameters, that is, the helix pitch (or helix rise) per residue h and the Kuhn segment length  −1 (the stiffness parameter or twice of the persistence length) as a function of Mw. Although the chain stiffness parameter  −1 for the corresponding linear polymer was reported to be 22 nm and 73 nm in MEA and MIBK, respectively, those for cADMPC in the three solvents were determined to be about 20 nm, this value being still significantly larger than that for cyclic amylose in aqueous sodium hydroxide. On the other hand, the former parameter h is somewhat larger than those for the linear ADMPC. The extended main chain of cADMPC by the topological constraint does not retain the chain stiffness as high as the corresponding linear chain. This phenomenon only becomes significant when the corresponding linear polymer behaves as a stiff chain with a small value of the Kuhn segment number NK. The threshold value of NK to achieve the significant difference in NK between the linear and cyclic chains is about less than 1.0 -1.5 at which the probability to link the both ends (ring closure probability) of the linear wormlike chain significantly decreases with decreasing NK.

To examine precise depth profiles at the interface of SiO2/SiC, a high resolution that can detect slight discrepancies in the distribution is needed. In this study, an experimental method to achieve a high resolution of less than 1 nm was developed by using dual‐beam time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS). The analysis was preceded by the following three steps: (1) determination of the optimal analytical conditions of the analysis beam (Bi+) and sputtering beam (Cs+), (2) verification of the etching methods to thin the SiO2 layer, and (3) confirmation of the benefits of the low‐energy sputtering beam directed toward SiO2/SiC samples. By using the secondary ion intensity peak‐to‐valley ratio of BN− and BO− of a sample with delta‐doped boron multilayers, the appropriate Bi+/Cs+ condition for a high depth resolution was determined for each energy level of the sputtering beam. Upon verification of the etching methods to thin the SiO2 layer, slight discrepancies were found between samples that were obtained with different etching methods. The difference in the roughness values of the etched surfaces was proactively utilized for the performance confirmation of the low‐energy sputtering beam by means of precise observation of the profiles at the SiO2/SiC interface. The use of a Cs beam with a low energy between 0.25 and 0.5 keV enabled the detection of slight discrepancies in the roughness of less than 1 nm between samples. The aforementioned method has the potential to accurately detect discrepancies in the intrinsic distribution at the SiO2/SiC interface among samples.

For precise investigation of distribution for impurity or composition at SiO2/SiC interface, dual-beam Time-of-flight Secondary ion mass spectrometry (TOF-SIMS) with low energy sputtering beam was available. In addition to the experimental profiles, simulation using MRI model, in which Mixing, Roughness and Information depth were employed as parameters, enabled to acquire a more authentic distribution at the SiO2/SiC interface. Slight discrepancy on depth profiles between samples with different surface roughness was duplicated on the convoluted profiles in the simulation. Moreover, reconstructed profile of nitrogen indicated a real distribution with less impact of mixing and roughness, although that may contain uncertainty due to incompletion in the simulation model or variation of the distribution owing to detection species in the experiment. From the result of carbon profiles of both experimental and convoluted profiles, the relative discrepancy on the carbon distribution between samples was clarified, which suggested the possibility that a carbon thin layer at the SiO2/SiC interface would be found in the future.