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Mesoporous silica nanoparticles (MSNs) are considered for potential scaffoldings in drug delivery due to their good biocompatibility and large pore volume, and it is the focus to find a suitable gatekeeper for the mesopores. In this paper, a reliable and versatile method of surface-initiated atom transfer radical polymerization (SI-ATRP) has been employed to prepare the hybrid poly(2-(diethylamino)ethyl methacrylate)-coated MSNs (MSN-PDEAEMA). The resultant hybrid nanoparticles with pH-sensitive polymer shell and MSN core were characterized by a series of techniques including high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, and nitrogen adsorption isotherms. The pH-responsive PDEAEMA brushes anchored on MSNs could serve as a switch to control the opening and closing of the pores. Release of guest molecules was conducted at different pHs, and the results showed rapid release in acidic aqueous solution but very little leakage in alkaline solution. By adjusting the pH of the solution repeatedly, the release of encapsulated molecules could be switched on and off at will. We envision that this nanosystem should have potential applications in sited release of anticancer drug and gene delivery.

The self-assembly of block copolymers attracts wide interest due to many potential applications of the polymeric aggregates. Great effort has been made to realize the convenient fabrication of abundant polymeric materials with well-defined nanostructures. This review introduces the development of the in situ preparation of block copolymer aggregates by heterogeneous polymerization. Great emphasis is put on discussing the formation mechanism of aggregates with different morphologies. Some important factors that influence the morphologies are illustrated when different polymerization methods are employed. By demonstrating some recent advances and existing problems in this area, more attention and effort should be paid to this field to facilitate its further progress.

A novel nanocontainer, which could regulate the release of payloads, has been successfully fabricated by attaching zwitterionic sulfobetaine copolymer onto the mesoporous silica nanoparticles (MSNs). RAFT polymerization is employed to prepare the hybrid poly(2-(dimethylamino)ethyl methacrylate)-coated MSNs (MSN-PDMAEMA). Subsequently, the tertiary amine groups in PDMAEMA are quaternized with 1,3-propanesultone to get poly(DMAEMA-co-3-dimethyl(methacryloyloxyethyl)ammonium propanesulfonate)-coated MSNs [MSN-Poly(DMAEMA-co-DMAPS)]. The zwitterionic PDMAPS component endows the nanocarrier with biocompatibility, and the PDMAEMA component makes the copolymer shell temperature-responsive. Controlled release of loaded rhodamine B has been achieved in the saline solutions.

Lignin-based polyurethane elastomers (LPUe) with high stiffness, strength, and toughness were facilely prepared by direct cross-linking of unfunctionized lignin as hard segments and poly­(propylene glycol) tolylene 2,4-diisocyanate terminated (PPGTDI) as soft domains. The effects of lignin molecular weight (3600 and 600 g mol–1) and weight fraction (5–40 wt %) on the thermal and mechanical properties of LPUe were studied. With an increase in lignin content, LPUe exhibited improved thermal stability, and the glass transition temperature (T g) also increased, especially for LPUe derived from lignin with low lignin molecular weight of 600 g mol–1 (600-LPUe). Furthermore, LPUe also exhibits excellent mechanical properties. For 600-LPUe with 40 wt % of lignin, the Young’s modulus, tensile strength, and strain at break reach 176.4 MPa, 33.0 MPa, and 1394%, respectively, which could be attributed to better dispersion of low molecular weight lignin in elastomers as evident from DSC, SEM, and TEM studies. Our results demonstrate the potential application of unmodified lignin in developing biobased high-performance PU materials. This is in contrast to many current studies of LPUe systems that need lignin modification to prepare PU materials.