Highly stable and permeable silicone emulsions were prepared by encapsulating N-octyl triethoaysilane microdroplets into micelles of NH_(2)-PDMS/SiO_(2).The conversion of siloxane to sub-1μm emulsions,on one hand,end...Highly stable and permeable silicone emulsions were prepared by encapsulating N-octyl triethoaysilane microdroplets into micelles of NH_(2)-PDMS/SiO_(2).The conversion of siloxane to sub-1μm emulsions,on one hand,endows the concrete with a highly hydrophobic internal surface.While,its outside surface maintains relatively high surface energy,which is beneficial for the post-coating of other polymers.As a result,the coated concreted can simultaneously acquire water repellency and low permeability.The utilization of water-dispersed silicone emulsions,on the other hand,is beneficial for the environmental protection.Thus,this work offered a green procedure for the comprehensive protection of concrete.展开更多
Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique t...Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique that is based on powder-bed fusion(PBF)to process metals;however,it is currently focused only on the fabrication of macroscale and mesoscale components.This paper reviews the state of the art of the SLM of metallic materials at the microscale level.In comparison with the direct writing techniques that are commonly used for micro AM,micro SLM is attractive due to a number of factors,including a faster cycle time,process simplicity,and material versatility.A comprehensive evaluation of various research works and commercial systems for the fabrication of microscale parts using SLM and selective laser sintering(SLS)is conducted.In addition to identifying existing issues with SLM at the microscale,which include powder recoating,laser optics,and powder particle size,this paper details potential future directions.A detailed review of existing recoating methods in powder-bed techniques is conducted,along with a description of emerging efforts to implement dry powder dispensing methods in the AM domain.A number of secondary finishing techniques for AM components are reviewed,with a focus on implementation for microscale features and integration with micro SLM systems.展开更多
基金Funded by Fundamental Research Funds for the Central Universities(No.2019MS062)City University of Hong Kong(No.SRG7004918)
文摘Highly stable and permeable silicone emulsions were prepared by encapsulating N-octyl triethoaysilane microdroplets into micelles of NH_(2)-PDMS/SiO_(2).The conversion of siloxane to sub-1μm emulsions,on one hand,endows the concrete with a highly hydrophobic internal surface.While,its outside surface maintains relatively high surface energy,which is beneficial for the post-coating of other polymers.As a result,the coated concreted can simultaneously acquire water repellency and low permeability.The utilization of water-dispersed silicone emulsions,on the other hand,is beneficial for the environmental protection.Thus,this work offered a green procedure for the comprehensive protection of concrete.
基金financial support from the Science and Engineering Research Council,Agency for Science,Technology and Research(A*STAR),Singapore(142 68 00088)
文摘Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique that is based on powder-bed fusion(PBF)to process metals;however,it is currently focused only on the fabrication of macroscale and mesoscale components.This paper reviews the state of the art of the SLM of metallic materials at the microscale level.In comparison with the direct writing techniques that are commonly used for micro AM,micro SLM is attractive due to a number of factors,including a faster cycle time,process simplicity,and material versatility.A comprehensive evaluation of various research works and commercial systems for the fabrication of microscale parts using SLM and selective laser sintering(SLS)is conducted.In addition to identifying existing issues with SLM at the microscale,which include powder recoating,laser optics,and powder particle size,this paper details potential future directions.A detailed review of existing recoating methods in powder-bed techniques is conducted,along with a description of emerging efforts to implement dry powder dispensing methods in the AM domain.A number of secondary finishing techniques for AM components are reviewed,with a focus on implementation for microscale features and integration with micro SLM systems.
