Two‐Component Gel‐Phase Materials—Highly Tunable Self‐Assembling Systems

Abstract

In the past 10 years, the molecular self-assembly and network formation of small molecule gelators has become one of the most active frontiers of the emergent area of nanochemistry. Increasingly, research efforts have begun to focus on multicomponent gelators, which rely on the initial interaction of distinct individual components to form a complex that subsequently self-assembles into a fibrous supramolecular polymer. In true two-component systems, an individual component can be present in isotropic solution, and only on addition of the second component will a gel actually form. In some cases, however, two-component gels are reported in which the second component significantly modifies the behaviour of a known gelator. Both systems are discussed in this article. The additional level of supramolecular control in the hierarchical self-assembly of two-component gels confers exquisite tunability and controllability. Functionality can be readily built into the material by simple variation of one of the individual components. This article discusses the key approaches used to control self-assembly by manipulating single molecular-recognition events and illustrates how controlling the transcription of information from the molecular to the macroscopic level by the simple addition of a second component allows complex functional materials to be selectively assembled from simple building blocks.

Investigation on the assembled structure–property correlation of supramolecular hydrogel formed from low-molecular-weight gelator

“…Indeed, gelation can be considered as a kind of controlled crystallization process [39]. Many researches tried to control the properties of gel phase materials based on com- Table 1 Influence of assembling condition on the fiber width, T gel and freezing water content of the gels formed at concentration of 5 wt% ponent structures [36,[40][41][42], solvent property [43][44][45] or the ratio of different components [7]. In this paper, the aggregate size and the gel property were easily controlled by the cooling speed and ultrasonic treatment.…”

“…In particular, supramolecular gels gelled by low-molecular-weight compounds (gelators) [4][5][6][7] have attracted great attention, owing to their versatile application in many areas, such as controlled drug release, oil recovery, tissue engineering and so on [8]. During formation of the hydrogel, the gelator molecules self-assemble into nanoscale superstructures, such as fibers, rods, and ribbons through hydrogen bonding, π-π stacking, van der Waals interactions, coordination and charge-transfer interactions.…”

Formation of supramolecular hydrogels with controlled microstructures and stability via molecular assembling in a two-component system

“…To our surprise, when cooling the hot aqueous solutions of their mixtures in air at 25 • C, hydrogels rather than crystals were obtained. The present two-component system is quite different from the traditional two-component gelation systems where two distinct, complementary components are used [11]. To our knowledge, hydrogelators with such simple structures have not yet been reported.…”

“…According to Hamilton's recent review [1], many different kinds of amphiphilic molecules can be used as effective hydrogelators, including conventional amphiphiles [6] with one polar head group and one or two hydrophobic tails, bolaamphiphiles [7] with two polar heads connected by a hydrophobic linker, gemini surfactants [8,9] with flexible tail-ion-linker-ion-flexible tail structure, sugar-based systems [10], and so on. In addition to one-component systems, hydrogels can be formed in two-component systems as well [11]. For example, Zhang et al [12] described supramolecular hydrogels with improved mechanical strength based on vancomycin and D-Ala-D-Ala derivative.…”

Self‐Assembly of Two‐Component Gels: Stoichiometric Control and Component Selection

“…Gelation systems which rely on the presence of two complementary components have an additional level of control in the hierarchical assembly process-initially the two components must form a complex, and only then can further assembly into nanoscale architectures take place. [4] A wide range of two-component systems based on different non-covalent interactions has been reported. [5][6][7][8] The two-component approach endows gel-phase materials with exquisite microstructural tunability, as either of the two components can be subtly modified.…”