Biocompatible polymers with non-traditional intrinsic luminescence possess the advantages of environmental friendliness and facile structural regulation, however, it is challenging to regulate the emission property. In this work, five kinds of hyperbranched polysiloxanes (HBPSi) with different alkane chain lengths are synthesized. Optical investigation shows that the emission wavelength of HBPSi is closely related to the alkane chain lengths, namely, short alkane chains will generate relative long-wavelength emission. Electronic communication among functional groups is responsible for the emission. HBPSi molecules aggregate together due to the strong hydrogen bond and amphiphilicity, the functional groups in the aggregate are so close that their electron clouds are overlapped and generate spatial electronic delocalizations. HBPSi with shorter alkane chains will generate larger electronic delocalizations and emit longer-wavelength emissions. Moreover, these polymers show excellent application in the fabrication of fluorescent films and chemical sensing. This work could provide a strategy for regulating the emission wavelength of unconventional fluorescent polymers.

Nonconventional luminescent materials have been rising stars in organic luminophores due to their intrinsic characteristics, including water-solubility, biocompatibility and environmental friendliness, and have shown potential applications in diverse fields. As an indispensable branch of nonconventional luminescent materials, polysiloxanes which consist of electron-rich auxochromic groups, have exhibited outstanding photophysical properties due to the unique silicon atom. The flexible Si-O bonds benefit the aggregation, and the empty 3d orbitals of Si atom can generate coordination bonds like N → Si and O → Si, altering the electron delocalization of the material and improving the luminescent purity. Herein, we review the recent progress in luminescent polysiloxanes with different topologies and discuss the challenges and perspectives. With an emphasis on the driving force for the aggregation and the mechanism of tuned emissions, the role of Si atoms played in the nonconventional luminophores is highlighted. This review may provide new insights into the design of nonconventional luminescent materials and expand their further applications in sensing, biomedicine, lighting devices, etc.

Crosslinking thermosets with hyperbranched polymers confers them superior comprehensive performance. However, it still remains a further understanding of polymer crosslinking from the molecular chains to the role of aggregates. In this study, three hyperbranched polysiloxane structures (HBPSi-R) are synthesized as model macromolecules, each featuring distinct terminal groups (R denotes amino, epoxy, and vinyl groups) while similar molecular backbone (Si-O-C). These structures were subsequently copolymerized with epoxy monomers to construct interpenetrating HBPSi-R/epoxy/anhydride co-polymer systems. The spatial molecular configuration and flexible Si-O-C branches of HBPSi-R endow them with remarkable reinforcement and toughening effects. Notably, an optimum impact strength of 28.9 kJ mol-1 is achieved with a mere 3% loading of HBPSi-V, nearly three times that of the native epoxy (12.9 kJ mol-1). By contrasting the terminal effects, the aggregation states and crosslinking modes were proposed, thus clarifying the supramolecular-dominant aggregation mechanism and covalent-dominant dispersion mechanism, which influences the resulting material properties. This work underscores the significance of aggregate science in comprehending polymer crosslinking and provides theoretical insights for tailoring material properties at a refined molecular level in the field of polymer science.