Preparation And Characterization On PH-sensitive Intelligent HPAN/Ge Hydrogels Fibers

The hydrogel fibers is that the character of material can respond to the changes in environment, such as temperature, pH, electric field, solvent, ray intensity, wavelength, pressure, ion intensity, chemical environment, etc. Generally, the change of character is elongation of volume, this change is consecutive or inconsecutive phase transition that stimulates by a special environment. The hydrogel fibers can be made to use in various fields, including chemical actuator, artificial muscle, drug transform and delivery system, specialized separation system and chemical muscle, etc.PAA hydrogels with -COOH is thought of the most representative responsive polymer gels. Based on PAN can be hydrolyzed to responsible -COOH and Ge （Gelatin） as bio-material is reproducible, decomposable and bio-compatible. We designed to prepare responsive HPAN/ Ge hygrogel fibers by solution spinning and then to study the stimuli-responsive behavior of the hydrogel fibers in the difference value of pH. The main contents are listed below:1. The preparation of HPAN/Ge intelligent hydrogel fibers and HPAN/Ge / Urea intelligent hydrogel fibers HPAN/Ge hydrogel fibers and HPAN/Ge / Urea hydrogel fibers were firstly obtained by solution spinning PAN hydrolyzed in NaOH solution, then composed with Ge. Ge firstly was modified by 3mol/L Urea solution, after modified the spin capability and compatible capability of HPAN/Ge fibers have been improved, microscope and SEM have identified this phenomenon.The fibers were coagulated in Na₂SO₄ coagulation bath, which has different percent chemically crosslink - glutaraldehyde. The carboxyl, the morphology structure of HPAN and hydrogel fibers was studied by FTR, CHNS/O Analyzer, SEM, Microscope.2. pH-sensitive behavior of HPAN/Ge intelligent hydrogel fibers and HPAN/Ge/Urea intelligent hydrogel fibers were studiedThe elongation/contraction hysteresis phenomenon of the HPAN/Ge hydrogel fiber and HPAN/Ge/Urea hydrogel fiber with the circular change of pH from 1.0 to 14.0 in environment solution was illuminated. The fibers have a good characteristic of reversible elongation/contraction phenomenon. When the crosslink percent is 1%, the temperature of solution is 25℃, The HPAN/Ge hydrogel fibers (w_PAN/w_Ge=3: 7) have quick response time, the elongation response time and contraction response time is 0.59 second and 1.14 second respectively, and that of the HPAN/Ge/Urea hydrogel fibers (w_HPAN/w_Ge = 5:5) is 0.55 second and 0.61 second respectively. The Equilibrium swelling elongation ratio decreases with the increasing of m_Ge%. The Equilibrium swelling elongation ratio of the HPAN/Ge/Urea hydrogel fibers decrease with the increasing of crosslink, and inconspicuous with increasing of environment temperature.