| 학회 | 한국고분자학회 |
| 학술대회 | 2005년 가을 (10/13 ~ 10/14, 제주 ICC) |
| 권호 | 30권 2호 |
| 발표분야 | 고분자 구조 및 물성 |
| 제목 | Intra- and inter-structural characterization of amphiphilic diblock copolymer using generalized indirect Fourier transformation technique |
| 초록 | Abstract: The inter- and intra-structure of amphiphilic diblock copolymer was studied using small angle X-ray scattering (SAXS) and Generalized Indirect Fourier Transform (GIFT) methods. The GIFT is the method of interpreting the intra-structure (such as size and shape) of particles, as well as the inter-structure between them1. The intensity scattered by particle could be expressed by where S(q) is structure factor, P(q) is form factor and N is the number of particles.2 If solution is dilute (S(q)1), intra-particular structure can be calculated directly with P(q), which can be transformed into p(r) (pair distance distribution function) by using indirect Fourier transform, and further into (r) (electron density distribution function) by using deconvolution method. As concentration increases, S(q), which we can analyze the inter-relationship between each particles with, should be taken into account to separate P(q) from I(q). The GIFT, developed by Otto Glatter, is a unique model-free method to determine P(q), S(q) as well as (r).* In this analysis, two models for the structure factor such as the averaged structure factor for polydisperse hard spheres are compared.3 The structure of poly[styrene-b-(4-vinylpyridine)](PS-b-P4VP)(12,000g/mol-11,800g/mol) in the solution state was studied for the application of GIFT as an example in this study. And in order to find out the relation between intra- or inter-structure in solution state and inter-structure in solid state, structure factor of PS-b-PVP in the gel state is analyzed. Figure 1 shows the normalized logI-logq plots of PS(12k)-b-PVP(11.8k) solution in toluene at the various concentrations. The intensity at low q decreased at the higher concentrations (larger than 4 wt%), indicating that the scattering from inter-particle interference plays an important role in intensity at higher concentrations. Figure 2 and 3 show the S(q) and p(r), respectively. The first intensity maximum of S(q) in Figure 2, which is indicative of the inter-particle distance, increased with increasing concentration due to the close distance between the particles. We separated the structure factor from the intensity to calculate the form factor which can be transformed into the pair distance distribution function as shown in Figure 3. The p(r)s at 0.25 wt%, 0.5wt%, 1wt% (which is the dilute system for comparison), 4wt%, 8wt% and 16wt% are nearly similar each other, suggesting that the structure factor was successfully separated from intensity and the size and shape of the particle could be analyzed from the form factor and the pair distance distribution function: in this case, the micelle structure is spherical one with the maximum diameter of 46.5nm. From this study, we found that the GIFT method was an appropriate method to analyze not only the inter-particular structure but also the intra-particular structure. |
| 저자 | 장윤정, 박수영 |
| 소속 | 경북대 |
| 키워드 | SAXS; micelle; ps-b-pvp |
