Dilute solution properties of semiflexible star and ring polymers

Abstract

Our recent theoretical and/or Monte Carlo (MC) studies of dilute solution properties of semiflexible stars and rings are briefly summarized. The theoretical results for the intrinsic viscosity [η] of the Kratky-Porod (KP) wormlike three-and four-arm stars are shown, and effects of chain stiffness on [η] of the stars are examined. A comparison of the results for [η] with those for the effective hydrodynamic radius and the second virial coefficient A 2 in a good solvent was made for the semiflexible three-arm stars. It was found that [η] is the most suitable object of study to examine the effects of chain stiffness on average chain dimensions of the stars. As for the rings, the MC results for A 2 of the ideal KP rings, which is related to the intermolecular topological interactions, are presented and then compared with the data in the literature for ring atactic polystyrene (a-PS) at Θ for large molecular weight M (1 × 10 4-6 × 10 5). Even for ring a-PS in such a range of M , the effects of chain stiffness were still remarkable. The effects of the intramolecular topological constraints on the mean-square radius of gyration and the scattering function of the KP rings are also discussed.

Living Ring-Expansion Polymerization of Thiirane with Cyclic Monocarbamothioates

“… The present cyclic polysulfides might extend more widely in solution and have less entanglement between polymer molecules compared with the linear polymers. These results are different from the theoretical validation results for dilute solutions using semiflexible star and ring polymers . These mean that both experimental and theoretical verifications are needed in the future.…”

“…These results are different from the theoretical validation results for dilute solutions using semiflexible star and ring polymers. 37 These mean that both experimental and theoretical verifications are needed in the future.…”

Interactions between ring polymers in dilute solution studied by Monte Carlo simulation

“…As the theoretical studies, des Cloizeaux 12 and Tanaka 13 argued topological effects in solution, while Deguchi et al 14 reported statistics of random knots and links with a Monte-Carlo (MC) simulation. Recently, Ida et al 15,16 evaluated A 2 values between semi-flexible ring polymers with a MC simulation, where the A 2 values were calculated from the potential energy and the interpenetration function between two rings, and the results were applied to those for ring polystyrene in the range of M n ≤ 10 5 . A large number of conformations were generated in their studies [9][10][11][14][15][16] and were classified by their topologies using the Gauss linking coefficient.…”

“…Recently, Ida et al 15,16 evaluated A 2 values between semi-flexible ring polymers with a MC simulation, where the A 2 values were calculated from the potential energy and the interpenetration function between two rings, and the results were applied to those for ring polystyrene in the range of M n ≤ 10 5 . A large number of conformations were generated in their studies [9][10][11][14][15][16] and were classified by their topologies using the Gauss linking coefficient. 17 Suzuki et al 18,19 reported that the topological constraint in trivial, 3 1 -, and 5 1 -knot ring polymers in the limited but fairly large N region, N ≤ 2048, where the ring polymers were isolated in the three dimensional lattice.…”

Novel Synthesis of Rigid Cyclic Polymers and Their Molecular Conformation and Intermolecular Interactions in Solution

“…や櫛形鎖 3,4) などの分岐構 造を含んでいても線状鎖との差が非常に小さいのに対し、環状鎖の場合、高分子間の 位相幾何学(トポロジー)的な相互作用が顕著に現れることが、実験的 5,6) にも理論的 [7][8][9][10] にも示されている。このような相互作用の違いは高分子の結晶化挙動や両親媒性 環状高分子の集合挙動に顕著な違いとして観察されることも最近報告されている [11][12][13][14][15] 。さらには、原核生物が遺伝情報の保存に環状の DNA を選択したこと 16) からも環 状高分子の分子形態や分子間相互作用は興味深い研究分野である。 このような環状高分子の溶液中における挙動は、制御重合により得られた線状高分 子の両末端をカップリング法により結合した合成環状高分子、 そして環状 DNA [17][18][19][20] に ついて主に調べられてきた。後者は二重らせん構造により環状化の際に生じるねじれ に伴う超らせん構造をとる 16) ため環状鎖のモデル分子としては必ずしも適切ではな い。また前者の手法は末端のカップリングの際に両末端の接触確率がある一定以上で ないと反応が進行しないため、屈曲性高分子に限られる。このため、線状鎖の溶液研 究が様々な局所形態 (剛直性) のものについて網羅的に調べられている 21,22) のに対し、 環状鎖の物性研究は前述の環状 DNA の他にはポリスチレン [23][24][25][26][27] Figure 2. Plots of (a) h vs fhyd and (b) λh vs fhyd for amylose tris(n-butylcarbamate) (ATBC) in various solvents 36,37) .…”