Polyurethane/silk protein-bismuth halide oxide composite films were fabricated using a blending-wet phase transformationin situsynthesis method. The crystal structure, micromorphology, and optical properties were conducted using XRD, SEM, and UV-Vis DRS characterize techniques. The results indicated that loaded silk protein enhanced the hydrophilicity and pore structure of the polyurethane composite films. The active species BiOX were observed to grow as nanosheets with high dispersion on the internal skeleton and silk protein surface of the polyurethane-silk protein film. The photocatalytic efficiency of BiOX/PU-SF composite films was assessed through the degradation of Rhodamine B under visible light irradiation. Among the tested films, the BiOBr/PU-SF composite exhibited the highest removal rate of RhB at 98.9%, surpassing the removal rates of 93.7% for the BiOCl/PU-SF composite and 85.6% for the BiOI/PU-SF composite. Furthermore, an active species capture test indicated that superoxide radical (•O2-) and hole (h+) species played a predominant role in the photodegradation process.

Polyurethane is widely used on the surface of composite materials for rotor blades as sand erosion protection materials. The failure mechanism investigation of polyurethane film under service conditions is useful for developing the optimal polyurethane film for rotor blades. In this article, the sand erosion test parameters were ascertained according to the service environment of the polyurethane film. The sand erosion resistance and failure mechanism of polyurethane film at different impact angles were analyzed by an infrared thermometer, a Fourier transform infrared spectrometer (FTIR), a differential scanning calorimeter (DSC), a field emission scanning electron microscope (FESEM), and a laser confocal microscope (CLSM). The results show that the direct measurement method of volume loss can better characterize the sand erosion resistance of the polyurethane film compared to traditional mass loss methods, which avoids the influence of sand particles embedded in the polyurethane film. The sand erosion resistance of polyurethane film at low-angle impact is much lower than that at high-angle impact. At an impact rate of 220 m/s, the volume loss after sand erosion for 15 min at the impact angle of 30° is 57.8 mm3, while that at the impact angle of 90° is only 2.6 mm3. The volume loss prediction equation was established according to the experimental data. During low-angle erosion, the polyurethane film damage is mainly caused by sand cutting, which leads to wrinkling and accumulation of surface materials, a rapid increase in roughness, and the generation of long cracks. The linking of developing cracks would lead to large-scale shedding of polyurethane film. During high-angle erosion, the polyurethane film damage is mainly caused by impact. The connection of small cracks caused by impact leads to the shedding of small pieces of polyurethane, while the change in the roughness of the film is not as significant as that during low-angle erosion. The disordered arrangement of the soft and hard blocks becomes locally ordered under the action of impact and cutting loads. Then, the disordered state is restored after the erosion test finishes. The erosion of sand particles leads to an increase in the temperature of the erosion zone of the polyurethane film, and the maximum temperature rise is 6 °C, which does not result in a significant change in the molecular structure of the polyurethane film. The erosion failure mechanism is cracking caused by sand cutting and impact.

OBJECTIVE: Radiation-induced skin reactions remain one of the most frequent side effects of adjuvant radiotherapy for breast cancer, which is the most common global malignancy. In individual cases, we observed a decrease in radiation dermatitis under film dressings used for skin marking purposes. Therefore, we decided to revise the available evidence regarding the prophylactic use of film dressings to reduce radiation dermatitis in breast cancer patients.
METHODS: On 20 March 2023, we conducted a systematic review of literature for randomized controlled trials published in the English, German, French, or Spanish language, available in the PubMed database.
RESULTS: Of 82 publications, 9 full texts were assessed and 6 randomized controlled trials were included in the final synthesis. Two trials analyzed the application of polyurethane film (Hydrofilm, Paul Hartmann AG, Heidenheim, Germany), the other four of silicone-based polyurethane film (Mepitel film, Molnlycke Health Care Limited, Milton Keynes, United Kingdom). The evaluation scales Common Terminology Criteria for Adverse Events (CTCAE), Radiation Therapy Oncology Group (RTOG), and the Radiation-Induced Skin Reaction Assessment Scale (RISRAS) were used for assessment. All six trials, with a total of 788 patients yielding data for analysis, demonstrate a significant decrease in radiation-induced skin reactions by use of the film (mainly p < 0.001).
CONCLUSIONS: Our analysis demonstrates a significant decrease in radiation-induced skin reactions by prophylactically applied film dressings in breast cancer patients. Consequent preventive use of film dressings might systematically reduce acute radiation-induced skin reactions in these patients.

Trauma, burns, and diabetes result in nonhealing wounds that can cause bone or tendon exposure, a significant health threat. The use of an artificial regeneration template combined with skin grafting as an alternative method to highly invasive flap surgery has been shown to be an effective way to cover full-thickness skin defects with bone or tendon exposure for both functional and aesthetic recovery. However, artificial regeneration templates, such as Pelnac, are overwhelmingly expensive, limiting their clinical use. Here, we demonstrate for the first time that polyurethane film combined with absorbable gelatine sponge, affordable materials widely used for haemostasis, are effective for dermal reconstruction in wounds with bone or tendon exposure. The absorbable gelatine sponge combined with polyurethane film was applied to eight patients, all resulting in adequate granulation that fully covered the exposed bone or tendon. The outcome of absorbable gelatine sponge combined with polyurethane film application indicates that this approach is a potential novel and cost-effective dermal reconstruction strategy for the treatment of severe wounds with bone or tendon exposure.

Flexible conductive thin films have recently become a research area of focus in both academia and industry. In this study, a method of preparing nanofiber conductive films by centrifugal spinning is proposed. Polyurethane (PU) nanofiber films were prepared by centrifugal spinning as the flexible substrate film, and carbon nanotubes (CNTs) were used as the conducting medium, to obtain CNTs/PU nanofiber conductive films with good conductivity and elasticity. The effects of different CNT concentrations on the properties of the nanofiber films were investigated. It was found that the conductivity of the nanofiber conductive films was optimal when an impregnation concentration of 9% CNTs was used in the stretching process. Cyclic tensile resistance tests showed that the nanofiber conductive films have good durability and repeatability. Physical and structural property analysis of the CNT/PU conductive films indicate that the adsorption of the CNTs on the PU surface was successful and the CNTs were evenly dispersed on the surface of the matrix. Moreover, the CNTs improved the thermal stability of the PU membrane. The CNT/PU conductive films were pasted onto a human finger joint, wrist joint, and Adam\'s apple to test the detection of movement. The results showed that finger bending, wrist bending, and laryngeal prominence movement all caused a change in resistance of the conductive film, with an approximately linear curve. The results indicate that the CNT/PU nanofiber conductive film developed in this study can be used to test the motion of human joints.

Programming such as stretching, compression and bending is indispensible to endow polyurethanes with shape memory effects. Despite extensive investigations on the contributions of programming processes to the shape memory effects of polyurethane, less attention has been paid to the nanostructures of shape memory polyurethanes surface during the programming process. Here we found that stretching could induce the reassembly of hard domains and thereby change the nanostructures on the film surfaces with dependence on the stretching ratios (0%, 50%, 100%, and 200%). In as-cast polyurethane films, hard segments sequentially assembled into nano-scale hard domains, round or fibrillar islands, and fibrillar apophyses. Upon stretching, the islands packed along the stretching axis to form reoriented fibrillar apophyses along the stretching direction. Stretching only changed the chemical patterns on polyurethane films without significantly altering surface roughness, with the primary composition of fibrillar apophyses being hydrophilic hard domains. Further analysis of osteoblasts morphology revealed that the focal adhesion formation and osteoblasts orientation were in accordance with the chemical patterns of the underlying stretched films, which corroborates the vital roles of stretching-induced nanostructures in regulating osteoblasts morphology. These novel findings suggest that programming might hold great potential for patterning polyurethane surfaces so as to direct cellular behavior. In addition, this work lays groundwork for guiding the programming of shape memory polyurethanes to produce appropriate nanostructures for predetermined medical applications.