CAJ | 학술논문

利用Monte Carlo模拟，对比了相同组成下环形二嵌段共聚物AB和线形三嵌段共聚物ABA在选择性溶剂中的胶束化行为。结果发现，相同链组成的环形和线形嵌段共聚物的临界胶束浓度( cmc)的差别与A嵌段的比例( fA )及B嵌段间的吸引强度(着)密切相关。在fA较小、着较大的情况下，相应环形嵌段共聚物的cmc值更小；而在fA较大、着较小的情况下，线形嵌段共聚物的cmc值更小。为了进一步理解胶束化行为同fA及着的关系，计算了胶束化过程中熵和势能部分对自由能的贡献。结果表明，在所研究的fA和着范围内，环形嵌段共聚物形成胶束时的熵损失更小，因而从熵贡献角度来看，环形嵌段共聚物更易发生胶束化。而从势能贡献角度来看，当fA较小、着较大时，环形嵌段共聚物形成胶束时势能有较大程度的降低，对自由能的贡献更大，因而此时环形嵌段共聚物更易发生胶束化。而当fA较大、着较小时，线形嵌段共聚物形成胶束时势能有较大程度的降低，对自由能的贡献更大，因而此时线形嵌段共聚物更易发生胶束化。由此可见，对体系的胶束化自由能进行系统分析，有助于更好地理解环形和线形嵌段共聚物的胶束化行为。
이용Monte Carlo모의，대비료상동조성하배형이감단공취물AB화선형삼감단공취물ABA재선택성용제중적효속화행위。결과발현，상동련조성적배형화선형감단공취물적림계효속농도( cmc)적차별여A감단적비례( fA )급B감단간적흡인강도(착)밀절상관。재fA교소、착교대적정황하，상응배형감단공취물적cmc치경소；이재fA교대、착교소적정황하，선형감단공취물적cmc치경소。위료진일보리해효속화행위동fA급착적관계，계산료효속화과정중적화세능부분대자유능적공헌。결과표명，재소연구적fA화착범위내，배형감단공취물형성효속시적적손실경소，인이종적공헌각도래간，배형감단공취물경역발생효속화。이종세능공헌각도래간，당fA교소、착교대시，배형감단공취물형성효속시세능유교대정도적강저，대자유능적공헌경대，인이차시배형감단공취물경역발생효속화。이당fA교대、착교소시，선형감단공취물형성효속시세능유교대정도적강저，대자유능적공헌경대，인이차시선형감단공취물경역발생효속화。유차가견，대체계적효속화자유능진행계통분석，유조우경호지리해배형화선형감단공취물적효속화행위。
The micellization behaviour of ring-like AB diblock copolymers in a selective solvent was compared with the corresponding linear ABA triblock copolymers via Monte Carlo simulation. The simulation results show that the difference in the critical micellization concentration ( cmc ) values between ring-like copolymers and linear copolymers with same compositions is closely related to the content of A blocks, fA, and the strength of attractive interaction between B monomers,ε. When fA is relatively small andεis big, the cmc values of ring-like block copolymers are smaller than those of the corresponding linear ones;whereas when fA is big andεis small, the cmc values of triblock copolymers are smaller than those of the corresponding ring-like ones. To fur-ther understand the effect of fA andεon the micellization behavior, we calculated the entropy and the potential energy contributions to the micellization free energy, respectively. The results show that in the studied range of fA andε, the entropy loss in micellization for ring-like block copolymers is always smaller than that for triblock copolymers, so it seems that the micellization of ring-like block copolymers is always easier than that of the linear ones if we only consider the entropy contributions to the free energy. But if we calculate the potential energy contributions to the free energy, it can be found when fA is relatively small and ε is big, the potential energy decreases greatly during the micellization of ring-like block copolymers. Considering the less unfavor-able contribution of entropy part to the free energy for ring-like block copolymers, the micellization of ring-like block copolymers should be much easier than that of the linear ones. When fA is big andεis small, the poten-tial energy decreases greatly when the micelles form for linear block copolymers. Although the entropic contri-bution to the free energy is unfavorable for linear ones, the potential energy still shows the dominative contri-bution to the free energy and therefore the micellization of linear block copolymers is much easier than the ring-like ones. The above analysis of the free energy will help us understand the micellization behavior of ring-like block copolymers and linear block copolymers.