Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
Adv Colloid Interface Sci. 2011 Nov 14;169(1):13-25. doi: 10.1016/j.cis.2011.07.002. Epub 2011 Jul 27.
Recently, cyclodextrins (CDs) were found to play important yet complicated (or even apparently opposite sometimes) roles in self-assembly systems of amphiphiles or surfactants. Herein, we try to review and clarify the versatility of CDs in surfactant assembly systems by 1) classifying the roles played by CDs into two groups (modulator and building unit) and four subgroups (destructive and constructive modulators, amphiphilic and unamphiphilic building units), 2) comparing these subgroups, and 3) analyzing mechanisms. As a modulator, although CDs by themselves do not participate into the final surfactant aggregates, they can greatly affect the aggregates in two ways. In most cases CDs will destroy the aggregates by depleting surfactant molecules from the aggregates (destructive), or in certain cases CDs can promote the aggregates to grow by selectively removing the less-aggregatable surfactant molecules from the aggregates (constructive). As an amphiphilic building unit, CDs can be chemically (by chemical bonds) or physically (by host-guest interaction) attached to a hydrophobic moiety, and the resultant compounds act as classic amphiphiles. As an unamphiphilic building unit, CD/surfactant complexes or even CDs on their own can assemble into aggregates in an unconventional, unamphiphilic manner driven by CD-CD H-bonds. Moreover, special emphasis is put on two recently appeared aspects: the constructive modulator and unamphiphilic building unit.
最近，环糊精（CDs）被发现于两亲分子或表面活性剂的自组装体系中扮演着重要但复杂（甚至有时明显相反）的角色。在此，我们试图通过以下方式来综述并阐明 CDs 在表面活性剂组装体系中的多功能性：1）将 CDs 所扮演的角色分为两组（调节剂和构筑单元）和四亚组（破坏型和建设性调节剂、两亲性和非两亲性构筑单元）；2）比较这些亚组；3）分析其机制。作为调节剂，尽管 CDs 本身并不参与最终的表面活性剂聚集体，但它们可以通过两种方式极大地影响聚集体。在大多数情况下，CDs 会通过从聚集体中耗尽表面活性剂分子来破坏聚集体（破坏型），或者在某些情况下，CDs 可以通过选择性地从聚集体中去除更不易聚集的表面活性剂分子来促进聚集体的生长（建设性）。作为两亲性构筑单元，CDs 可以通过化学键（通过化学键）或物理键（通过主客体相互作用）连接到疏水性部分，所得化合物作为经典两亲体。作为非两亲性构筑单元，CD/表面活性剂复合物甚至单独的 CDs 可以以非常规的非两亲性方式组装成聚集体，这是由 CD-CD H 键驱动的。此外，特别强调了最近出现的两个方面：建设性调节剂和非两亲性构筑单元。
