田川 由美子

<p><tt>周波数38 kHz および130 kHz の市販超音波洗浄機を用いて水溶液中で超音波洗浄を行ない，周波数，洗浄液組成，および照射方向の効果を調べた．洗浄基質には，ポリエチレンテレフタレートフィルムおよびポリエステル布を用い，汚れ物質には，カーボンブラック（CB）および着色オレイン酸を使用した．洗浄液には，塩化ナトリウム（NaCl）水溶液，NaCl 水溶液に水酸化ナトリウム（NaOH）またはドデシル硫酸ナトリウム（SDS）を添加した水溶液を用いた．洗浄性評価は，フィルムは顕微鏡画像解析法，布は表面反射率法を用いた．その結果，フィルムからのCB の洗浄率は，同じ超音波出力（W）では38 kHz の方が洗浄率は高かった．布洗浄では，NaOH およびSDS の添加効果が認めら れた．さらに，38 kHz の試作超音波洗浄機を用いて照射方向を変えて布洗浄を行い，洗浄率および洗浄ムラへの影響を調べ</tt><tt>た．</tt></p>

The effect of ultraviolet light irradiation on the characteristics of the polyethylene (PE) surface was investigated by the quartz crystal microbalance (QCM) technique. The PE film was prepared on the gold electrodes of the QCM by spin-coating from the solution and then was treated by the excimer UV lamp in ambient air. The changes in the hydrophilic properties, moisture adsorption, and water retention of the PE film due to the UV irradiation were determined from the frequency change of the QCM. To evaluate the detergency of the PE film, stearic acid as model oily soil was deposited onto the PE film formed on the QCM by the Langmuir-Blodgett (LB) technique, and was ultrasonically cleaned in aqueous detergent solutions containing ethanol or surfactant. The removal efficiency obtained from the frequency change of the QCM was found to increase considerably after the UV irradiation. From independently determined contact angles and the surface free energy components of the PE film, the free energy change resulting from the penetration of the detergent solution between stearic acid and PE in the zone of contact was calculated. Good relation was found between the removal efficiency and the free energy change, indicating that the increase in the detergency of the PE surface by UV irradiation was explained by surface energetics.<br>

水晶振動子法を用いて水溶液中での固体粒子汚れの洗浄性について調べ, 表面自由エネルギーに基づいて検討を行った。洗浄基質には, 水晶振動子の金電極表面および電極にポリエチレン, ナイロン6, トリアセテートをスピンコート法により被覆した膜表面を用いた。モデル粒子汚れには, ポリエチレン粒子およびナイロン12粒子を用いた。基質への粒子の付着は, 水晶振動子を粒子分散液に垂直に浸漬する方法で行なった。分散液から基質を引き上げて空気中で乾燥した後, エタノール添加または無添加の水溶液中で粒子の洗浄を行った.洗浄率は付着前後および洗浄前後の周波数変化から算出した。洗浄率は粒子および基質により異なるが, いずれの系でもエタノールの添加により洗浄が促進された。3種類の指標液体の接触角から, 汚れおよび基質の表面自由エネルギーのLifshitz-van der Waals成分と酸一塩基成分を求めた。本研究で得られた固体粒子汚れの洗浄現象は表面自由エネルギーから算出した脱離の自由エネルギー変化により説明できることがわかった.

Soil deposition on fibers was investigated from the standpoint of the waste water treatment. Polyethylene, poly (vinylidene chloride), poly (vinylidene fluoride), polyethylene terephthalate and nylon 6 fibers were used as soil collectors. Following immersion of the fibers in water from Sarusawa pond, water turbidity was measured. Turbidity decreased due to the deposition of soil onto the fiber surfaces. Poly (vinylidene chloride) fibers were more effective as a soil collector than any other fibers.<BR>Particle deposition from an aqueous solution was investigated using a model system consisting of spherical polyethylene or nylon particles and a polymeric plate. The plate was perpendicularly immersed in an aqueous suspension. The number of particles deposited on the plate appeared related to the polar components of surface free energies of the particle and plate. The results of particle deposition in the model system were in good agreement with those in systems using water from a pond.

Adhesion and removal phenomena in aqueous solutions were investigated using spherical polyethylene particles and a quartz plate. The experimental results are discussed and explained on the basis of the heterocoagulation theory, using ζ-potentials of the particles and the quartz plate as determined by micro-electrophoresis. The magnitude of the energy barrier preventing particle adhesion was found to be about 4000 κT for particles of 4-5μm in diameter. The Hamaker constant (A₁₁) of a polyethylene particle was estimated by the adhesion and removal phenomena and was determined as 6.06.8×10^-13ergs from curves of interaction energy plotted against separation.