Dioctadecyldimethylammonium bromide (DODAB) is known to self-assemble into several lamellar structures in water, existing as either liquid crystalline, gel, or coagel phases. In this work, by using differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction techniques, we have characterized the details of the phase transition mechanisms of the DODAB aqueous dispersions. It was found that the liquid crystalline converts to the coagel phase via a two-step mechanism: first to the gel phase upon cooling and then to the stable coagel phase. Although significant conformational changes in the hydrocarbon tails were observed in both steps, changes in the headgroups of DODAB were only detected in the second step. More interestingly, we found that the lipid tails change prior to the headgroups during the overall liquid crystalline to coagel phase transformation process. This is regarded as a nonsynchronicity phenomenon, which reflects the regional (head/tail) imbalance in molecular interactions. Such a nonsynchronicity phenomenon in the self-assembled aggregates composed of the medium-sized DODAB molecules will shed light on our understanding of the polymorphism and reversibility of amphiphiles including both surfactants and biomembrane phospholipids.

Controlling liquid–solid triboelectrification is highly demanded in a wide range of applications, from electrostatic prevention to energy collection and utilization. Except for traditional unidirectional and irreversible ways, smart approaches are required urgently. Here, a novel temperature response liquid–solid triboelectric nanogenerator (TENG) is reported on the basis of a polycaprolactone (PCL) covered fluorinated alumina for tunable triboelectrification. The PCL conformation is regulated by temperature to endow the substrate controllable surface component and interfacial wettability to manipulate the liquid–solid triboelectricity flexibly. As the temperature rises from 20 to 40 °C, the short circuit current and the open‐circuit voltage of the PCL‐based TENG are reduced by more than 40 times. When the temperature drops to 20 °C, the electrical output can return to its original level again. Moreover, after one month, the electrical signal is still reversible and stable. In addition to water, the electrical output of organic liquid, such as ethylene glycol, also responds well to temperature. This work initially provides a new strategy for achieving the customizable manipulation of liquid–solid triboelectrification by polymer surface reorganization, gives a new idea for in situ monitoring the interfacial wettability changes, and configures the reconstruction of amphiphilic polymer using triboelectricity.

The hydrogen bonding properties of a representative molecule, 2-mercaptoethanol (ME), of which two functional groups OH and SH are believed to interact competitively or selectively with proton-accepting molecules, have been studied. Three binary systems, namely ME-CCl(4), ME-dimethyl sulfoxide (DMSO), and ME-acetone, were investigated with excess infrared absorption spectroscopy. It is found that when DMSO or acetone is added into ME, they preferentially form hydrogen bonds with OH, and the hydrogen bonds in the ME-DMSO system are stronger than those in the ME-acetone system. When CCl(4) is added into ME, the weak hydrogen bonds involving the SH group are broken preferentially with increasing CCl(4) concentration. The dissociation process of ME in the inert diluent CCl(4) over the entire concentration range has been discussed in detail. In the very low concentration range of CCl(4), the highly hydrogen bonded ME multimers mainly break into medium-sized aggregates. The amount of the trimers and dimers first increases and then, at x(CCl(4)) = 0.77, begins to decrease. These results suggest that excess infrared spectroscopy can provide detailed molecular pictures in liquid solutions containing complex hydrogen bonding interactions. It can also help to locate individual peak positions in the deconvolution of overlapped absorption bands.