A series of oxidized hyaluronic acid (oxi‐HA)/3,3′‐dithiobis (propionohydrazide) (DTP) redox responsive hydrogels by Schiff base reaction under physiological conditions were designed and prepared. The influence of the concentration of oxi‐HA and DTP on rheological properties, equilibrium swelling ratio, and degradation rate were investigated. All oxi‐HA/DTP hydrogels exhibited good rheological properties, high equilibrium swelling ratio, low degradation rate, and sustainable drug release properties, and the comprehensive performance of oxi‐HA5/DTP6 hydrogel was better than that of others. The redox responsiveness was evaluated by means of degradation and in vitro bovine serum albumin release behavior investigation with the stimulus of different concentration of dithiothreitol as reducing agent. The intelligent hydrogels could be potentially applied in the fields of drug delivery system, tissue engineering, or cell scaffold materials. Copyright © 2017 John Wiley & Sons, Ltd.

A series of injectable in situ cross-linking hyaluronic acid/carboxymethyl cellulose based hydrogels (HA/CMC) was prepared via disulfide bonds by the oxidation of dissolved oxygen. The results showed that HA/CMC hydrogels exhibited tunable gelling time, appropriate rheology properties, high swelling ratio, good stability, and sustained drug release ability. The gelling time of HA/CMC hydrogels ranged from 1.4 to 7.0 min, and the values of the storage modulus, complex shear modulus, dynamic viscosity, and yield stress of HA3/CMC3 hydrogel were about 5869 Pa, 5870 Pa, 587 Pa·s, and 1969 Pa, respectively. The degradation percentage of HA1/CMC1, HA2/CMC2, and HA3/CMC3 hydrogels were about 60, 49, and 41% after incubating 42 days, and the in vitro cumulative release percentage of BSA from HA1/CMC1, HA2/CMC2, and HA3/CMC3 drug-loaded hydrogels were about 99, 91, and 82% after 30 days. The series of injectable in situ cross-linking HA/CMC hydrogels exhibited good comprehensive performance, signifying that these hydrogels could be potentially used in the fields of short- and medium-term controlled drug release, cell encapsulation, regenerative medicine, and tissue engineering.

The hybridization of siloxane‐ and carbosilane‐based structures in molecular scale could combine their advantages of high thermal resistance and low dielectric constant. However, the hybridization still remained a big challenge in lacking convenient synthesis method. Herein, in this work, we developed a new method via simultaneous Grignard and sol–gel reactions of (chrolomethyl)trimethoxysilane to directly generate siloxane/carbosilane hybridized oligomers with hyperbranched structure. The oligomers were subsequently functionalized by benzocyclobutene and cured to produce crosslinked resins. As‐resulted resins have low dielectric constant (~2.60) as compared with silica and higher thermal stability compared with polycarbosilane. The integrated high performance and facile preparation for these resins make them potentially used as low dielectric materials in integrating circuits insulating and wave transmitting.

Three original conjugated polymers were devised and synthesized via the alternating conjugated polymerization of the electron-donating monomer of the modified benzo[1,2-b:4,5-b']dithiophene (BDT) and electronaccepting monomers of perylene diimide (PDI), dithienyl-perylene diimide (DTPDI) and dithienocoronene diimide (DTCDI), respectively. The synthesized conjugated polymers presented excellent thermal stability (T d >400 o C) as well as broad absorption in visible region and narrow gap of energy level (1.80 to 2.01 eV). Moreover, P(BDT-DTCDI) exhibited strong fluorescence properties ( =736 nm with excitation at 680 nm). According to the theoretical calculations, P(BDT-PDI) and P(BDT-DTPDI) displayed significant polymer backbone torsion (41.44 o and 39.64 o ), and P(BDT-DTCDI) had highly coplanar backbone with negligible angle between BDT and DTCDI. The results indicated that P(BDT-DTCDI) had potential applications in the fields of organic thin-film transistors (OTFTs) and fluorescence materials, and P(BDT-PDI) and P(BDT-DTPDI) could be used as a stable n-type semiconductor for polymer solar cells.

Benzocyclobutene-modified silsesquioxane (BCB-POSS) and divinyl tetramethyl disiloxane-bisbenzocyclobutene (DVS-BCB) prepolymer were introduced into the containing benzocyclobutene (BCB) unit matrix resin P(4-MB-co-1-MP) polymerized from 1-methyl-1-(4-benzocyclobutenyl) silacyclobutane (4-MSCBBCB) and 1-methyl-1-phenylsilacyclobutane (1-MPSCB), respectively. The low dielectric constant (low-k) siloxane/carbosilane hybrid benzocyclobutene resin composites, P(4-MB-co-1-MP)/BCB-POSS and P(4-MB-co-1-MP)/DVS-BCB, were prepared. The curing processes of the composites were assessed via Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The effects on dielectric properties and heat resistance of those composites with different proportion of BCB-POSS and DVS-BCB were investigated using an impedance analyzer and thermogravimetric analyzer (TGA), respectively. The thermal curing of composites could be carried out by ring-opening polymerization (ROP) of the BCB four-member rings of BCB-POSS or DVS-BCB and those of P(4-MB-co-1-MP). With increasing the proportion of BCB-POSS to 30%, the 5% weight loss temperature (T5%) of P(4-MB-co-1-MP)/BCB-POSS composites was raised visibly, whereas the dielectric constant (k) was decreased owing to the introduction of nanopores into POSS. For P(4-MB-co-1-MP)/DVS-BCB composites, the T5% and k were slightly raised with increasing the proportion of DVS-BCB. The above results indicated that the BCB-POSS showed advantages over conventional fillers to simultaneously improve thermostability and decrease k.

The route via the cross-linking of hyperbranched prepolymers has potential advantage to construct low dielectric constant (low-k) resins owing to the enhanced molecular free volume in hyperbranched structure. However, it is still a challenge to prepare hyperbranched resins with good film-forming property and low-k. In this paper, two hyperbranched polycarbosilanes with reactive benzocyclobutene groups were synthesized via hydrosilylation reaction to avoid the generation of Si O bonds for enabling the low polarity of chemical bonds. The spacing groups including phenyl or ethylene were incorporated into the hyperbranched structures, and the effect of the spacing groups on the physicochemical properties of hyperbranched polycarbosilane derived resins were investigated. The phenyl groups were found to effectively decrease the dielectric constant (k), while endowing the resins with good film forming ability and thermostability. The UV/thermally cured phenyl group resin owing to dual crosslinked structure, the patterns would not be deformed significantly during thermally cured process. Both hyperbranched polycarbosilane derived resins could be potential photoresists.

Based on the excellent physical properties and flexible molecular modifiability, modified silicone resins have received favorable attention in the field of microelectronics, and recently a number of modified silicone resins have appeared while few breakthroughs have been made in low dielectric constant (low-k) materials field due to the limitations of structure or the curing process. In this work, functional silicone resin with different BCB contents was prepared with two monomers. The resins showed low dielectric constant (k = 2.77 at 10 MHz) and thermal stability (T5% = 495.0 °C) after curing. Significant performance changes were observed with the increase in BCB structural units, and the functional silicone obtained does not require melting and dissolution during processing because of good fluidity at room temperature. Moreover, the mechanical properties of silicone resins can be also controlled by adjusting the BCB content. The obtained silicone resins could be potentially used in the field of electronic packaging materials.

A series of injectable hydrogels was prepared by cross-linking oxidized carboxymethyl cellulose (oxi-CMC) with polyacryloyl hydrazide (PAH) via a Schiff base reaction under physiological conditions. The hydrogels exhibited superior performance such as appropriate rheology properties, high swelling ratio, and low degradation rate. In phosphate buffer solution (PBS, pH 7.4) at 37°C, the swelling ratio of the hydrogels ranged from 19 to 28 after 7 h, the degradation percentage of the oxi-CMC6/PAH3 hydrogel was ~47 % after 20 days. Using bovine serum albumin (BSA) as a model protein drug, the results of in vitro drug release studies demonstrated that the sustained release of BSA could be cooperatively controlled through drug diffusion and hydrogel degradation in PBS (pH 7.4) at 37°C, and the cumulative release percentage of BSA from a drug-loaded oxi-CMC6/PAH3 hydrogel was ~88 % after 8 days. The results signified that oxi-CMC6/PAH3 hydrogel could be potentially applied in the fields of drug delivery vehicles, tissue engineering, and cell encapsulation materials.