Microfluidic devices have become a powerful tool for chemical and biologic applications.To control dif-ferent functional parts on the microchip,valve plays a key role in the device.In conventional methods,physio-mechanical valves are usually used on microfluidic chip.Herein,we reported a chemo-mechanical switchable valve on microfluidic chip by using a thermally responsive block copolymer.The wettability changes of capillary with copolymer modification on inner surface were investigated to verify the func-tion as a valve.Capillaries with modification of poly-(N-isopropylacrylamide-co-hexafluoroisopropyl acry-late)(P(NIPAAm-co-HFIPA))with a 20％HFIPA was demonstrated capable of control aqueous solution stop or go through.Then short capillaries with copolymer modification were integrated in microchannels as valves.With the temperature changing around lower critical solution temperature(LCST),the integrated chemo-mechanical switchable valve exhibited excellent"OPEN-CLOSE"behavior for microflow control.After optimization of the block copolymer sequences and molar ratio,a switching time as low as 20 s was achieved.The developed micro valve was demonstrated effective for flow control on microchip.

Sifeng Mao;Xiaohong Hu;Yumi Tanaka;Lin Zhou;Chenhan Peng;Nahoko Kasai;Hizuru Nakajima;Shungo Kato;Katsumi Uchiyama

Department of Applied Chemistry,Graduate School of Urban Environmental Sciences,Tokyo Metropolitan University,Hachioji-shi,Tokyo 192-0397,Japan;University Education Center,Tokyo Metropolitan University,Hachioji-shi,Tokyo 192-0397,Japan

中国化学快报（英文版）

[1]Sifeng Mao;Xiaohong Hu;Yumi Tanaka;Lin Zhou;Chenhan Peng;Nahoko Kasai;Hizuru Nakajima;Shungo Kato;Katsumi Uchiyama-.A chemo-mechanical switchable valve on microfluidic chip based on a thermally responsive block copolymer)[J].中国化学快报（英文版）,2022(06):3083-3086

Capillaries,hexafluoroisopropyl,acry,HFIPA,CLOSE

chemo,mechanical,switchable,microfluidic,thermally,responsive,block,copolymer,Microfluidic,devices,have,become,powerful,tool,chemical,biologic,applications,To,control,ferent,functional,parts,microchip,plays,key,role,In,conventional,methods,physio,valves,are,usually,used,Herein,reported,by,using,wettability,changes,capillary,modification,inner,surface,were,investigated,verify,isopropylacrylamide,late,NIPAAm,was,demonstrated,capable,aqueous,solution,stop,go,through,Then,short,capillaries,integrated,microchannels,With,temperature,changing,around,lower,critical,LCST,exhibited,excellent,OPEN,behavior,microflow,After,optimization,sequences,molar,ratio,switching,achieved,developed,effective

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