Low Dielectric Benzocyclobutene-type Polymers Based on Facile Synthesis of Linear Fluorinated Monomer

A linear fluorinated benzocyclobutene-type monomer(4F-bis-BCB) was facilely synthesized by a one-step copper-catalyzed etherification reaction and a simple precipitation post-purification method.Moreover,a series of BCB-based polymeric low-dielectric(low-k)materials were obtained by the thermal-induced ring-opening copolymerization of 4F-bis-BCB with divinyl tetramethyl disiloxanebisbenzocyclobutene(DVS-BCB) monomer and further simple thermal curing at high temperature(200-300℃).The resultant fully cured materials demonstrated excellent low dielectric properties at high frequency of 10 GHz(dielectric constant(D_(k))<2.6,dielectric loss(D_(f))<1.57×10^(-2)),great hydrophobicity(water contact angle>116°),ultra-low water absorption(<0.19% after soaked in water at room temperature for 60 h) and excellent planarization ability(surface roughness<0.56 nm of 3 μm-thick film).Overall,this new fluorinated BCB-type monomer provides us an alternative for the facile preparation of low-k polymeric materials and exhibits great potential for future applications in high-frequency communication and three-dimensional high-density packaging technologies.

Flexible electrical stimulation device with Chitosan-Vaseline®dressing accelerates wound healing in diabetes

The healing process of diabetic wounds is typically disordered and prolonged and requires both angiogenesis and epithelialization.Disruptions of the endogenous electric fields(EFs)may lead to disordered cell migration.Electrical stimulation(ES)that mimics endogenous EFs is a promising method in treating diabetic wounds;however,a microenvironment that facilitates cell migration and a convenient means that can be used to apply ES are also required.Chitosan-Vaseline■gauze(CVG)has been identified to facilitate wound healing;it also promotes moisture retention and immune regulation and has antibacterial activity.For this study,we created a wound dressing using CVG together with a flexible ES device and further evaluated its potential as a treatment for diabetic wounds.We found that high voltage monophasic pulsed current(HVMPC)promoted healing of diabetic wounds in vivo.In studies carried out in vitro,we found that HVMPC promoted the proliferation and migration of human umbilical vein endothelial cells(HUVECs)by activating PI3K/Akt and ERK1/2 signaling.Overall,we determined that the flexible ES-chitosan dressing may promoted healing of diabetic wounds by accelerating angiogenesis,enhancing epithelialization,and inhibiting scar formation.These findings provide support for the ongoing development of this multidisciplinary product for the care and treatment of diabetic wounds.