•PBO nanofibers are used as a polymeric building block to assemble layered films.•(PBO-PBO)50 films possess outstanding thermal stability and fire retardancy.•(PBO-PVA)50 nanocomposites exhibit enhanced mechanical strength and flexibility.Assembling nanoscale building blocks derived from ultrastrong polymer fibers into ordered architectures should offer an effectively alternative way to access high-performance nanocomposites with extremely high strength and heat resistance for advanced applications. Poly(p-phenylenebenzobisoxazole) (PBO) fibers possess outstanding mechanical and thermal properties among the synthetic organic fibers. Here, commercial PBO fibers have been disintegrated into uniform nanofibers with the diameter of ca. 20 nm by a mixed acid treatment, and then served as a polymeric building block to be assembled into layered architectures through layer-by-layer deposition. The resulting (PBO-PBO)50 films exhibit superior mechanical and thermomechanical properties with the modulus of 3.29 GPa, the toughness of 2.1 MJ m−3, and the strength of 181.08 MPa. Through employing the poly(vinyl alcohol) (PVA) as a connecting layer in the deposition, the (PBO-PVA)50 nanocomposite films possess remarkable mechanical properties demonstrated by the modulus of 6.48 GPa, the toughness of 4.6 MJ m−3, and the strength of 304.34 MPa, due to the synergistic interfacial interaction between the PBO nanofibers and the matrix. In addition, the (PBO-PBO)50 films possess the thermal stability up to 625 °C and excellent fire retardancy.

The use of a near-infrared (NIR) laser for reversible modulation of a bubble-driven Janus polymer capsule motor is demonstrated. This process was mediated through illumination of the metal face of the Janus capsule motor at the critical concentration of peroxide fuel. Such an effective control of the propulsion of chemically powered microengines holds a considerable promise for diverse applications.

We present herein a novel hybrid, polymer-based motor that was fabricated by the template-assisted polyelectrolyte layer-by-layer (LbL) deposition of a thin gold layer on one side, followed by chemical immobilization of a catalytic enzyme. Such Janus capsule motors can self-propel at 0.1% peroxide fuel concentration at physiological temperature and have a higher speed as compared to Pt-based synthetic motors. They were exploited for encapsulation of the chemotherapeutic anticancer drug, doxorubicin, for navigation to target a cell layer by an external magnetic field, and for triggered drug release activated by NIR light. This work provides high potential in the development of multifunctional polymer-based engines for biomedical applications such as targeted drug delivery.

The use of a near-infrared (NIR) laser for reversible modulation of a bubble-driven Janus polymer capsule motor is demonstrated. This process was mediated through illumination of the metal face of the Janus capsule motor at the critical concentration of peroxide fuel. Such an effective control of the propulsion of chemically powered microengines holds a considerable promise for diverse applications.